JP5568605B2 - Photocatalyst coating agent using photocatalyst, photocatalyst dispersion, photocatalyst - Google Patents
Photocatalyst coating agent using photocatalyst, photocatalyst dispersion, photocatalyst Download PDFInfo
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- JP5568605B2 JP5568605B2 JP2012166619A JP2012166619A JP5568605B2 JP 5568605 B2 JP5568605 B2 JP 5568605B2 JP 2012166619 A JP2012166619 A JP 2012166619A JP 2012166619 A JP2012166619 A JP 2012166619A JP 5568605 B2 JP5568605 B2 JP 5568605B2
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- JP
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- Prior art keywords
- photocatalyst
- titanium oxide
- light
- iron oxyhydroxide
- wavelength
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 239000011941 photocatalyst Substances 0.000 title claims description 121
- 239000011248 coating agent Substances 0.000 title claims description 18
- 239000006185 dispersion Substances 0.000 title claims description 18
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 173
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 149
- CUPCBVUMRUSXIU-UHFFFAOYSA-N [Fe].OOO Chemical compound [Fe].OOO CUPCBVUMRUSXIU-UHFFFAOYSA-N 0.000 claims description 73
- 229910021519 iron(III) oxide-hydroxide Inorganic materials 0.000 claims description 73
- IKHGUXGNUITLKF-UHFFFAOYSA-N Acetaldehyde Chemical compound CC=O IKHGUXGNUITLKF-UHFFFAOYSA-N 0.000 claims description 56
- 239000002245 particle Substances 0.000 claims description 46
- 230000001699 photocatalysis Effects 0.000 claims description 44
- 238000000354 decomposition reaction Methods 0.000 claims description 23
- 239000011230 binding agent Substances 0.000 claims description 10
- 239000002612 dispersion medium Substances 0.000 claims description 9
- 239000000758 substrate Substances 0.000 claims description 5
- GHDSNRQFECQVII-UHFFFAOYSA-N [Ti].OOO Chemical compound [Ti].OOO GHDSNRQFECQVII-UHFFFAOYSA-N 0.000 claims 4
- 238000000034 method Methods 0.000 description 37
- 229910052783 alkali metal Inorganic materials 0.000 description 26
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 24
- 150000001340 alkali metals Chemical class 0.000 description 22
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 22
- 150000002506 iron compounds Chemical class 0.000 description 22
- 239000011734 sodium Substances 0.000 description 20
- -1 alkali metal titanate Chemical class 0.000 description 18
- 150000001342 alkaline earth metals Chemical class 0.000 description 17
- 239000007788 liquid Substances 0.000 description 17
- 239000000463 material Substances 0.000 description 17
- 239000002609 medium Substances 0.000 description 16
- JZQOJFLIJNRDHK-CMDGGOBGSA-N alpha-irone Chemical compound CC1CC=C(C)C(\C=C\C(C)=O)C1(C)C JZQOJFLIJNRDHK-CMDGGOBGSA-N 0.000 description 15
- 229910000859 α-Fe Inorganic materials 0.000 description 15
- 230000000052 comparative effect Effects 0.000 description 14
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 description 14
- 238000010438 heat treatment Methods 0.000 description 13
- 238000004519 manufacturing process Methods 0.000 description 13
- 230000000694 effects Effects 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 12
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 11
- 238000010304 firing Methods 0.000 description 11
- 229910052708 sodium Inorganic materials 0.000 description 11
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 10
- 150000001875 compounds Chemical class 0.000 description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 10
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 9
- 238000002156 mixing Methods 0.000 description 9
- 239000000047 product Substances 0.000 description 9
- 239000004408 titanium dioxide Substances 0.000 description 9
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 8
- 238000004813 Moessbauer spectroscopy Methods 0.000 description 8
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 8
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 8
- 238000004458 analytical method Methods 0.000 description 8
- 239000002270 dispersing agent Substances 0.000 description 8
- 239000000126 substance Substances 0.000 description 8
- 238000011282 treatment Methods 0.000 description 8
- 238000001914 filtration Methods 0.000 description 7
- 239000007789 gas Substances 0.000 description 7
- 239000000243 solution Substances 0.000 description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 238000001035 drying Methods 0.000 description 6
- 238000010335 hydrothermal treatment Methods 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 230000003472 neutralizing effect Effects 0.000 description 6
- 150000003388 sodium compounds Chemical class 0.000 description 6
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 description 6
- 238000005406 washing Methods 0.000 description 6
- 230000032683 aging Effects 0.000 description 5
- 150000001412 amines Chemical class 0.000 description 5
- 239000007864 aqueous solution Substances 0.000 description 5
- 239000002585 base Substances 0.000 description 5
- 150000007514 bases Chemical class 0.000 description 5
- 238000011156 evaluation Methods 0.000 description 5
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 5
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 229920001296 polysiloxane Polymers 0.000 description 5
- 239000002243 precursor Substances 0.000 description 5
- 239000000725 suspension Substances 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 238000010521 absorption reaction Methods 0.000 description 4
- 238000000862 absorption spectrum Methods 0.000 description 4
- 229910021529 ammonia Inorganic materials 0.000 description 4
- 230000003373 anti-fouling effect Effects 0.000 description 4
- 239000012298 atmosphere Substances 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 229920001577 copolymer Polymers 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 4
- 235000014413 iron hydroxide Nutrition 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 229910000029 sodium carbonate Inorganic materials 0.000 description 4
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 4
- 238000001228 spectrum Methods 0.000 description 4
- LLZRNZOLAXHGLL-UHFFFAOYSA-J titanic acid Chemical compound O[Ti](O)(O)O LLZRNZOLAXHGLL-UHFFFAOYSA-J 0.000 description 4
- 229910000349 titanium oxysulfate Inorganic materials 0.000 description 4
- 239000011787 zinc oxide Substances 0.000 description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 239000008119 colloidal silica Substances 0.000 description 3
- 230000005284 excitation Effects 0.000 description 3
- 239000010419 fine particle Substances 0.000 description 3
- 150000004679 hydroxides Chemical class 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 235000019353 potassium silicate Nutrition 0.000 description 3
- 150000003377 silicon compounds Chemical class 0.000 description 3
- 239000004094 surface-active agent Substances 0.000 description 3
- WUPHOULIZUERAE-UHFFFAOYSA-N 3-(oxolan-2-yl)propanoic acid Chemical compound OC(=O)CCC1CCCO1 WUPHOULIZUERAE-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 239000003463 adsorbent Substances 0.000 description 2
- 150000001339 alkali metal compounds Chemical class 0.000 description 2
- 150000001341 alkaline earth metal compounds Chemical class 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 229910052980 cadmium sulfide Inorganic materials 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 2
- 150000007942 carboxylates Chemical class 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 150000001805 chlorine compounds Chemical class 0.000 description 2
- 239000004927 clay Substances 0.000 description 2
- 239000004567 concrete Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000018044 dehydration Effects 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- 230000001877 deodorizing effect Effects 0.000 description 2
- 150000002148 esters Chemical class 0.000 description 2
- 150000002170 ethers Chemical class 0.000 description 2
- 229960004887 ferric hydroxide Drugs 0.000 description 2
- 239000000945 filler Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- KWIUHFFTVRNATP-UHFFFAOYSA-N glycine betaine Chemical compound C[N+](C)(C)CC([O-])=O KWIUHFFTVRNATP-UHFFFAOYSA-N 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 235000013980 iron oxide Nutrition 0.000 description 2
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 2
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 description 2
- IEECXTSVVFWGSE-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Fe+3] IEECXTSVVFWGSE-UHFFFAOYSA-M 0.000 description 2
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 2
- 239000004570 mortar (masonry) Substances 0.000 description 2
- 238000006386 neutralization reaction Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- DCKVFVYPWDKYDN-UHFFFAOYSA-L oxygen(2-);titanium(4+);sulfate Chemical compound [O-2].[Ti+4].[O-]S([O-])(=O)=O DCKVFVYPWDKYDN-UHFFFAOYSA-L 0.000 description 2
- 235000021317 phosphate Nutrition 0.000 description 2
- 238000013032 photocatalytic reaction Methods 0.000 description 2
- 229920000058 polyacrylate Polymers 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000011164 primary particle Substances 0.000 description 2
- 229910000077 silane Inorganic materials 0.000 description 2
- ORVGYTXFUWTWDM-UHFFFAOYSA-N silicic acid;sodium Chemical compound [Na].O[Si](O)(O)O ORVGYTXFUWTWDM-UHFFFAOYSA-N 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 230000001954 sterilising effect Effects 0.000 description 2
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 2
- 150000003609 titanium compounds Chemical class 0.000 description 2
- 229910000348 titanium sulfate Inorganic materials 0.000 description 2
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 2
- UXFQFBNBSPQBJW-UHFFFAOYSA-N 2-amino-2-methylpropane-1,3-diol Chemical compound OCC(N)(C)CO UXFQFBNBSPQBJW-UHFFFAOYSA-N 0.000 description 1
- MOMKYJPSVWEWPM-UHFFFAOYSA-N 4-(chloromethyl)-2-(4-methylphenyl)-1,3-thiazole Chemical compound C1=CC(C)=CC=C1C1=NC(CCl)=CS1 MOMKYJPSVWEWPM-UHFFFAOYSA-N 0.000 description 1
- RNIHAPSVIGPAFF-UHFFFAOYSA-N Acrylamide-acrylic acid resin Chemical compound NC(=O)C=C.OC(=O)C=C RNIHAPSVIGPAFF-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical group [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 229910002588 FeOOH Inorganic materials 0.000 description 1
- 239000004606 Fillers/Extenders Substances 0.000 description 1
- 239000005909 Kieselgur Substances 0.000 description 1
- 229910018068 Li 2 O Inorganic materials 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 241000047703 Nonion Species 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- GSEJCLTVZPLZKY-UHFFFAOYSA-N Triethanolamine Chemical group OCCN(CCO)CCO GSEJCLTVZPLZKY-UHFFFAOYSA-N 0.000 description 1
- DIFFLMNDXWOKQJ-UHFFFAOYSA-N [K].O[Si](O)(O)O Chemical compound [K].O[Si](O)(O)O DIFFLMNDXWOKQJ-UHFFFAOYSA-N 0.000 description 1
- AWSZRNUJNSWBRK-UHFFFAOYSA-N [Li].[Si](O)(O)(O)O Chemical compound [Li].[Si](O)(O)(O)O AWSZRNUJNSWBRK-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 229920006322 acrylamide copolymer Polymers 0.000 description 1
- 230000000274 adsorptive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910001860 alkaline earth metal hydroxide Inorganic materials 0.000 description 1
- 125000003545 alkoxy group Chemical group 0.000 description 1
- 150000003973 alkyl amines Chemical class 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 150000001413 amino acids Chemical class 0.000 description 1
- CBTVGIZVANVGBH-UHFFFAOYSA-N aminomethyl propanol Chemical compound CC(C)(N)CO CBTVGIZVANVGBH-UHFFFAOYSA-N 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- 239000002518 antifoaming agent Substances 0.000 description 1
- 239000003429 antifungal agent Substances 0.000 description 1
- 229940121375 antifungal agent Drugs 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 239000003125 aqueous solvent Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Inorganic materials [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 description 1
- 229960003237 betaine Drugs 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 125000006297 carbonyl amino group Chemical group [H]N([*:2])C([*:1])=O 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 210000003298 dental enamel Anatomy 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 239000003995 emulsifying agent Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 229960002089 ferrous chloride Drugs 0.000 description 1
- 239000011790 ferrous sulphate Substances 0.000 description 1
- 235000003891 ferrous sulphate Nutrition 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 125000005843 halogen group Chemical group 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 1
- 229910021506 iron(II) hydroxide Inorganic materials 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 229910000000 metal hydroxide Inorganic materials 0.000 description 1
- 150000004692 metal hydroxides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000012046 mixed solvent Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- SOQBVABWOPYFQZ-UHFFFAOYSA-N oxygen(2-);titanium(4+) Chemical class [O-2].[O-2].[Ti+4] SOQBVABWOPYFQZ-UHFFFAOYSA-N 0.000 description 1
- 239000003002 pH adjusting agent Substances 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 239000000123 paper Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
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- 239000002244 precipitate Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 150000003242 quaternary ammonium salts Chemical class 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
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- 229910052703 rhodium Inorganic materials 0.000 description 1
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- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 150000004756 silanes Chemical class 0.000 description 1
- 125000005372 silanol group Chemical group 0.000 description 1
- 229920002050 silicone resin Polymers 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- FQENQNTWSFEDLI-UHFFFAOYSA-J sodium diphosphate Chemical compound [Na+].[Na+].[Na+].[Na+].[O-]P([O-])(=O)OP([O-])([O-])=O FQENQNTWSFEDLI-UHFFFAOYSA-J 0.000 description 1
- 235000019983 sodium metaphosphate Nutrition 0.000 description 1
- ZNCPFRVNHGOPAG-UHFFFAOYSA-L sodium oxalate Chemical compound [Na+].[Na+].[O-]C(=O)C([O-])=O ZNCPFRVNHGOPAG-UHFFFAOYSA-L 0.000 description 1
- 229940039790 sodium oxalate Drugs 0.000 description 1
- 239000001488 sodium phosphate Substances 0.000 description 1
- 229910000162 sodium phosphate Inorganic materials 0.000 description 1
- 229940048086 sodium pyrophosphate Drugs 0.000 description 1
- 229940032158 sodium silicate Drugs 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 235000019794 sodium silicate Nutrition 0.000 description 1
- 235000019832 sodium triphosphate Nutrition 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 150000004763 sulfides Chemical class 0.000 description 1
- 150000003871 sulfonates Chemical class 0.000 description 1
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 description 1
- 235000019818 tetrasodium diphosphate Nutrition 0.000 description 1
- 239000001577 tetrasodium phosphonato phosphate Substances 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/88—Handling or mounting catalysts
- B01D53/885—Devices in general for catalytic purification of waste gases
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
- B01J23/74—Iron group metals
- B01J23/745—Iron
-
- B01J35/39—
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/14—Paints containing biocides, e.g. fungicides, insecticides or pesticides
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
- C09D7/40—Additives
- C09D7/60—Additives non-macromolecular
- C09D7/61—Additives non-macromolecular inorganic
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/20—Metals or compounds thereof
- B01D2255/207—Transition metals
- B01D2255/20707—Titanium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/20—Metals or compounds thereof
- B01D2255/207—Transition metals
- B01D2255/20738—Iron
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/80—Type of catalytic reaction
- B01D2255/802—Photocatalytic
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/20—Oxides; Hydroxides
- C08K3/22—Oxides; Hydroxides of metals
Description
本発明は、光触媒及びその製造方法並びにそれを用いた光触媒コート剤、光触媒分散体、光触媒体に関し、さらに詳細には、白色蛍光灯等の光照射によっても優れた触媒活性を有する光触媒に関する。 The present invention relates to a photocatalyst, a method for producing the same, a photocatalyst coating agent, a photocatalyst dispersion, and a photocatalyst using the photocatalyst, and more particularly relates to a photocatalyst having excellent catalytic activity even when irradiated with light such as a white fluorescent lamp.
光触媒は、そのバンドギャップ以上のエネルギーを持つ波長の光を照射すると励起し、強い触媒活性が発現するものである。特に、有機物やＮＯｘなどの一部無機物の酸化・分解力が大きく、エネルギー源として低コストで、環境負荷の非常に小さい光を利用できることから、近年環境浄化や脱臭、防汚、殺菌などへの応用が進められている。また、光触媒が励起するとその表面が親水性になり水との接触角が低下することが見出され、この作用を利用して防曇、防汚などへの応用も進められている。光触媒としては、酸化物や硫化物などの金属化合物が、特に、高い光触媒活性を有する微粒子の酸化チタン、酸化亜鉛などが一般的に用いられている。酸化チタン、酸化亜鉛などは、励起光の波長が４００ｎｍ以下の紫外線領域にある。例えば、酸化チタン粒子の内部及び／または表面に、酸化鉄、水酸化鉄、オキシ水酸化鉄等の鉄化合物を含有させ、光触媒活性を向上させる技術（特許文献１参照）が知られている。また、酸化チタン粒子の表面に１０〜１００Åの酸化第二鉄の微粒子を担持させて太陽光の利用効率を高める技術（特許文献２参照）、アナターゼ型酸化チタンの粒子表面に酸化第一鉄、酸化第二鉄、マグネタイト等の鉄酸化物を担持させて可視光線の照射によって高い活性を得る技術（特許文献３参照）も提案されている。 A photocatalyst is excited when irradiated with light having a wavelength greater than its band gap, and exhibits a strong catalytic activity. In particular, the ability to oxidize and decompose some inorganic substances such as organic substances and NOx is large, and light can be used as an energy source at a low cost and with a very low environmental load. Application is underway. Further, it has been found that when the photocatalyst is excited, its surface becomes hydrophilic and the contact angle with water is lowered, and application to antifogging, antifouling and the like is being promoted utilizing this action. As the photocatalyst, metal compounds such as oxides and sulfides, and particularly fine particles of titanium oxide and zinc oxide having high photocatalytic activity are generally used. Titanium oxide, zinc oxide, and the like are in the ultraviolet region where the wavelength of excitation light is 400 nm or less. For example, a technique for improving the photocatalytic activity by containing an iron compound such as iron oxide, iron hydroxide, or iron oxyhydroxide inside and / or on the surface of titanium oxide particles is known (see Patent Document 1). Further, a technology for increasing the utilization efficiency of sunlight by supporting fine particles of 10-100 第二 ferric oxide on the surface of titanium oxide particles (see Patent Document 2), ferrous oxide on the particle surface of anatase-type titanium oxide, A technique (see Patent Document 3) in which iron oxides such as ferric oxide and magnetite are supported and high activity is obtained by irradiation with visible light has been proposed.
可視光照射によって光触媒活性を有する光触媒は、紫外線ランプなど特別な光源が必要でなく、太陽光や白色蛍光灯などの光源を用いることができるので、光触媒の応用分野が更に広がることが期待されているが、特許文献２及び３に記載の光触媒では、白色蛍光灯等の光照射下での光触媒活性は十分ではない。そこで、本発明は、白色蛍光灯等の照射によって優れた光触媒活性を有する光触媒及びその製造方法を提供することを目的とする。 A photocatalyst having photocatalytic activity by irradiation with visible light does not require a special light source such as an ultraviolet lamp, and a light source such as sunlight or a white fluorescent lamp can be used. However, the photocatalysts described in Patent Documents 2 and 3 do not have sufficient photocatalytic activity under light irradiation such as a white fluorescent lamp. Then, an object of this invention is to provide the photocatalyst which has the outstanding photocatalytic activity by irradiation, such as a white fluorescent lamp, and its manufacturing method.
本発明者らは前記の特許文献１に基づいて、白色蛍光灯でも優れた活性を有する酸化チタン光触媒を開発するために鋭意研究を重ねた結果、種々の鉄化合物の中でも白色蛍光灯の光に含まれる４００〜５００ｎｍの波長の光を吸収するオキシ水酸化鉄を併用することにより、このようなオキシ水酸化鉄と酸化チタンを含む光触媒が白色蛍光灯の光照射下で、オキシ水酸化鉄を用いずに同じ条件で測定した酸化チタンに比べ約２倍以上の光触媒活性を有することを見出し、本発明を完成した。 Based on the above-mentioned Patent Document 1, the present inventors have intensively studied to develop a titanium oxide photocatalyst having excellent activity even in white fluorescent lamps. By using iron oxyhydroxide that absorbs light with a wavelength of 400 to 500 nm contained together, the photocatalyst containing such iron oxyhydroxide and titanium oxide can convert iron oxyhydroxide under light irradiation of a white fluorescent lamp. It was found that the photocatalytic activity was about twice or more that of titanium oxide measured under the same conditions without using it, and the present invention was completed.
すなわち、本発明は、次の点に特徴がある。
（１）少なくともオキシ水酸化鉄と酸化チタンを含む光触媒であって、オキシ水酸化鉄が４００〜５００ｎｍの波長の光を吸収することによって酸化チタンが光触媒活性を発現する光触媒である。このような光触媒は、４００〜５００ｎｍの波長の光を含む白色蛍光灯の光を照射した際のアセトアルデヒド分解反応速度定数が、同じ条件で測定した前記酸化チタンのアセトアルデヒド分解反応速度定数に対して、約２倍以上の光触媒活性を有する。
（２）本発明の光触媒の製造方法では、少なくともオキシ水酸化鉄と酸化チタンとを混合すること、より好ましくは、アルカリ金属元素及び／またはアルカリ土類金属元素を含有する酸化チタンを含む媒液中に、鉄化合物を添加し反応させて、該酸化チタンの粒子表面にオキシ水酸化鉄を担持することなどにより、オキシ水酸化鉄と酸化チタンを含有させる。
（３）少なくともオキシ水酸化鉄と酸化チタンを含む光触媒に、バインダーを配合することにより光触媒コート剤として、また、分散媒を配合することにより光触媒分散体とすることができる。また、少なくともオキシ水酸化鉄と酸化チタンを含む光触媒を成形したり、基材上に固定したりすることができる。
That is, the present invention is characterized by the following points.
(1) A photocatalyst containing at least iron oxyhydroxide and titanium oxide, wherein the titanium oxide exhibits photocatalytic activity when the iron oxyhydroxide absorbs light having a wavelength of 400 to 500 nm. Such a photocatalyst has an acetaldehyde decomposition reaction rate constant when irradiated with light from a white fluorescent lamp containing light having a wavelength of 400 to 500 nm, with respect to the acetaldehyde decomposition reaction rate constant of the titanium oxide measured under the same conditions. The photocatalytic activity is about twice or more.
(2) In the method for producing a photocatalyst of the present invention, at least iron oxyhydroxide and titanium oxide are mixed, more preferably, a liquid medium containing titanium oxide containing an alkali metal element and / or an alkaline earth metal element. An iron compound is added and reacted, and iron oxyhydroxide and titanium oxide are contained, for example, by supporting iron oxyhydroxide on the surface of the titanium oxide particles.
(3) A photocatalyst coating agent can be formed by blending a binder with a photocatalyst containing at least iron oxyhydroxide and titanium oxide, and a photocatalyst dispersion can be formed by blending a dispersion medium. In addition, a photocatalyst containing at least iron oxyhydroxide and titanium oxide can be molded or fixed on a substrate.
本発明の光触媒は、４００〜５００ｎｍの波長を有する白色蛍光灯等の光照射下で優れた光触媒活性を有しているので、紫外線ランプなどの特殊な光源を必要とせずに、蛍光灯などの室内照明や太陽光でも、ＮＯｘや有機の環境汚染物質などを効果的に分解する。親水性効果も期待できるので、浄化材、脱臭材、防汚材、殺菌材、防曇材等として好適なものである。また、酸化チタン、オキシ水酸化鉄といった比較的安価な材料を用いているので、低コストの光触媒を提供できる。
更に、本発明の光触媒は、コート剤、分散体などの液状組成物とすることができ、また、成形したり、基材に固定したりして光触媒体とすることができ、これらを用いて防汚性や親水性などの機能性を付与することができる。
Since the photocatalyst of the present invention has excellent photocatalytic activity under light irradiation such as a white fluorescent lamp having a wavelength of 400 to 500 nm, it does not require a special light source such as an ultraviolet lamp, and can be used for a fluorescent lamp or the like. Even indoor lighting and sunlight effectively decompose NOx and organic environmental pollutants. Since a hydrophilic effect can also be expected, it is suitable as a purifying material, a deodorizing material, an antifouling material, a sterilizing material, an antifogging material and the like. Further, since a relatively inexpensive material such as titanium oxide or iron oxyhydroxide is used, a low-cost photocatalyst can be provided.
Furthermore, the photocatalyst of the present invention can be a liquid composition such as a coating agent or a dispersion, and can be molded or fixed to a base material to form a photocatalyst, Functionality such as antifouling property and hydrophilicity can be imparted.
本発明は、少なくともオキシ水酸化鉄と酸化チタンを含む光触媒であって、オキシ水酸化鉄が４００〜５００ｎｍの波長の光を吸収することによって酸化チタンが光触媒活性を発現する。このため、光触媒活性の評価基準として、４００〜５００ｎｍの波長の光を含む白色蛍光灯の光を照射した際のアセトアルデヒド分解反応速度定数を測定し（後述の評価１を参照）、これにより活性を評価する。このようにして評価した本発明の光触媒の活性は、同じ条件で測定した酸化チタン自体の活性（アセトアルデヒド分解反応速度定数で評価）に対して、好ましくは約２倍以上、より好ましくは約５倍以上、更に好ましくは約７倍以上、最も好ましくは約１０倍以上である。本発明の光触媒は、少なくともオキシ水酸化鉄と酸化チタンを含むものであれば良いが、オキシ水酸化鉄が４００〜５００ｎｍの波長の光を吸収することによって酸化チタンが光触媒活性を発現するために、オキシ水酸化鉄と酸化チタンとが相互作用する程度に接合した状態が好ましく、それらが強固に接合した状態がより好ましい。このような状態とするには、オキシ水酸化鉄と酸化チタンとを混合することが好ましく、より好ましくは混合機を用いて混合し、更に好ましくはオキシ水酸化鉄と酸化チタンを懸濁状態で撹拌機等を用いて混合する。好ましくはオキシ水酸化鉄は酸化チタンの粒子表面に担持されている。オキシ水酸化鉄の担持様態は制限されず、酸化チタン粒子表面に吸着した状態であっても、酸化チタン粒子が表面に有する水酸基と水素結合するなどして強固に結合した状態であっても良い。本発明の光触媒、光触媒コート剤、光触媒分散体及び光触媒体においては、オキシ水酸化鉄、酸化チタン以外に酸化亜鉛、硫化カドミウムなどの光触媒性物質、各種吸着剤などが適宜含まれていても良く、その含有形態は特に限定されない。 The present invention is a photocatalyst containing at least iron oxyhydroxide and titanium oxide, and titanium oxide exhibits photocatalytic activity when iron oxyhydroxide absorbs light having a wavelength of 400 to 500 nm. Therefore, as an evaluation standard for photocatalytic activity, an acetaldehyde decomposition reaction rate constant when irradiated with light from a white fluorescent lamp containing light having a wavelength of 400 to 500 nm is measured (see Evaluation 1 described later), and the activity is thereby increased. evaluate. The activity of the photocatalyst of the present invention thus evaluated is preferably about 2 times or more, more preferably about 5 times the activity of titanium oxide itself (evaluated by the acetaldehyde decomposition reaction rate constant) measured under the same conditions. More preferably, it is about 7 times or more, most preferably about 10 times or more. The photocatalyst of the present invention only needs to contain at least iron oxyhydroxide and titanium oxide. However, since iron oxyhydroxide absorbs light having a wavelength of 400 to 500 nm, titanium oxide exhibits photocatalytic activity. A state where the iron oxyhydroxide and the titanium oxide are bonded to each other is preferable, and a state where they are firmly bonded is more preferable. In order to achieve such a state, it is preferable to mix iron oxyhydroxide and titanium oxide, more preferably using a mixer, and more preferably iron oxyhydroxide and titanium oxide in a suspended state. Mix using a stirrer or the like. Preferably, iron oxyhydroxide is supported on the particle surface of titanium oxide. The supporting state of iron oxyhydroxide is not limited, and may be in a state of being adsorbed on the surface of the titanium oxide particles or in a state of being firmly bonded by, for example, hydrogen bonding with the hydroxyl groups on the surface of the titanium oxide particles. . In the photocatalyst, photocatalyst coating agent, photocatalyst dispersion, and photocatalyst of the present invention, in addition to iron oxyhydroxide and titanium oxide, photocatalytic substances such as zinc oxide and cadmium sulfide, and various adsorbents may be included as appropriate. The containing form is not particularly limited.
本発明の光触媒に含まれるオキシ水酸化鉄は、ＦｅＯＯＨまたはＦｅ２Ｏ３・ｎＨ２Ｏの化学式で表される化合物であって、α態、β態、γ態等の結晶性のもの、あるいは無定形のものを用いることができる。特にα−オキシ水酸化鉄は４００〜５００ｎｍの波長の光の吸収効果が高く、より優れた活性を有する光触媒を与えるので好ましい。オキシ水酸化鉄の含有量は適宜設定できるが、オキシ水酸化鉄と酸化チタンの合量に対しＦｅ換算で０．０１〜５重量％の範囲にあるのが好ましく、０．０５〜２重量％の範囲が更に好ましい。酸化チタンがオキシ水酸化鉄を含有あるいは担持しているか、より詳細には、α態のオキシ水酸化鉄を含有あるいは担持しているかなどは、例えば、メスバウアー分光法や電子顕微鏡などで確認することができる。 The iron oxyhydroxide contained in the photocatalyst of the present invention is a compound represented by a chemical formula of FeOOH or Fe 2 O 3 .nH 2 O, which is crystalline such as α-form, β-form, γ-form, or An amorphous one can be used. In particular, α-iron oxyhydroxide is preferable because it has a high absorption effect on light having a wavelength of 400 to 500 nm and provides a photocatalyst having more excellent activity. The content of iron oxyhydroxide can be set as appropriate, but is preferably in the range of 0.01 to 5% by weight in terms of Fe with respect to the total amount of iron oxyhydroxide and titanium oxide, and 0.05 to 2% by weight The range of is more preferable. Whether the titanium oxide contains or carries iron oxyhydroxide, more specifically, whether or not it contains or carries α-type iron oxyhydroxide is confirmed by, for example, Mossbauer spectroscopy or an electron microscope. be able to.
本発明の光触媒に含まれる酸化チタンとしては、一般的なチタンの酸化物の他に、無水酸化チタン、含水酸化チタン、水和酸化チタン、水酸化チタン、チタン酸などと呼ばれるものが含まれ、アナターゼ型やルチル型など結晶形には制限は無く、不定形であっても良く、それらが混合したものであっても良い。これらの中でも、特に結晶性の高いものは、光触媒活性が高いため好ましく、ルチル型酸化チタンの励起光の波長はアナターゼ型よりもやや大きいので、ルチル型結晶を有する酸化チタンがより好ましい。また、酸化チタンの一部がチタン酸アルカリ金属、チタン酸アルカリ土類金属等の複合酸化物であっても良く、このような酸化チタンの内部には、その複合酸化物を構成するアルカリ金属元素、アルカリ土類金属元素が含まれるため好ましい。また、酸化チタンには、その励起に悪影響を与えない程度であれば、Ｖ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ｒｕ、Ｒｈ、Ｐｄ、Ａｇ、Ａｕから選ばれる１種以上の異種元素または酸化物等の異種元素の化合物が含まれていても良い。酸化チタンの大きさも制限されないが、ＢＥＴ法による比表面積が１０〜４００ｍ２／ｇ程度の範囲にあるのが好ましく、１０〜２００ｍ２／ｇ程度の範囲がより好ましく、１０〜１００ｍ２／ｇ程度の範囲が更に好ましく、３０〜８０ｍ２／ｇ程度の範囲が最も好ましい。比表面積が前記範囲より小さ過ぎると、有機物、窒素酸化物等の処理対象物質の吸着力が低下して分解効率が低下するため好ましくなく、大き過ぎると、微細になり過ぎて結晶性が高いものが得られ難いため好ましくない。 Titanium oxide contained in the photocatalyst of the present invention includes what is called anhydrous titanium oxide, hydrous titanium oxide, hydrated titanium oxide, titanium hydroxide, titanic acid, etc. in addition to general titanium oxides, There is no limitation on the crystal form such as anatase type or rutile type, and it may be indefinite or in a mixture thereof. Among these, those having particularly high crystallinity are preferable because of high photocatalytic activity, and the wavelength of excitation light of rutile type titanium oxide is slightly larger than that of anatase type, and therefore, titanium oxide having rutile type crystal is more preferable. Moreover, a part of the titanium oxide may be a complex oxide such as an alkali metal titanate or an alkaline earth titanate metal, and the inside of the titanium oxide contains an alkali metal element constituting the complex oxide. Since alkaline earth metal elements are contained, it is preferable. In addition, the titanium oxide has at least one kind of different element selected from V, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, and Au as long as it does not adversely affect the excitation. A compound of a different element such as an oxide may be included. Is also not limited the size of the titanium oxide is preferably a specific surface area by the BET method is in the range of about 10 to 400 m 2 / g, more preferably in the range of about 10~200m 2 / g, 10~100m 2 / g approximately Is more preferable, and a range of about 30 to 80 m 2 / g is most preferable. If the specific surface area is too smaller than the above range, it is not preferable because the adsorptive power of organic substances, nitrogen oxides and other substances to be treated is reduced and the decomposition efficiency is lowered, and if it is too large, it becomes too fine and has high crystallinity. Is not preferred because it is difficult to obtain.
酸化チタンの粒子形状にも制限は無く、真球状、略球状、異方性形状等の定形粒子や、粒塊状等の不定形粒子等を用いることができる。特に異方性形状を有するものであれば、優れた光触媒活性が得られ易く好ましい。本発明で言う「異方性形状」とは、一般的には、紡錘状粒子、棒状粒子、針状粒子、板状粒子等と呼ばれるものであり、一個の一次粒子を最も安定な状態で平面上に静止させ、平面上への投影像を二つの平行線で挟み、その平行線の間隔が最小となるときの距離を粒子の幅または短軸径ｗ、この２平行線に直角な方向の二つの平行線で粒子を挟むときの距離を粒子の長さまたは長軸径ｌ、最大安定面に平行な面で挟むときの距離を粒子の高さｈとした場合、ｌ＞ｗ≧ｈを満たすものを言う。長軸径、短軸径、高さは、一次粒子を電子顕微鏡写真から、約１０００個の粒子の算術平均値により求めることができる。本発明で用いる異方性形状を有する酸化チタンの大きさは、前述のようにＢＥＴ法による比表面積が１０〜２００ｍ２／ｇ程度の範囲がより好ましく、１０〜１００ｍ２／ｇ程度の範囲が更に好ましく、３０〜８０ｍ２／ｇ程度の範囲が最も好ましい。このような異方性形状粒子としては、１０〜５００ｎｍの範囲の平均長軸径と、１〜２５ｎｍの範囲の平均短軸径とを有するものが好ましく、中でも、軸比（平均長軸径／平均短軸径）が１．５以上の紡錘状粒子、棒状粒子、針状粒子と呼ばれるものが好ましく、軸比が１．５〜１０の範囲にあればより好ましく、さらに好ましくは２〜７の範囲である。 There is no restriction | limiting also in the particle shape of a titanium oxide, Regular particles, such as a spherical shape, substantially spherical shape, and anisotropic shape, amorphous particles, such as agglomerate shape, etc. can be used. In particular, those having an anisotropic shape are preferable because excellent photocatalytic activity is easily obtained. The “anisotropic shape” as used in the present invention is generally called a spindle-shaped particle, a rod-shaped particle, a needle-shaped particle, a plate-shaped particle or the like, and a single primary particle is planarized in the most stable state. The projection image on the plane is sandwiched between two parallel lines, and the distance when the distance between the parallel lines is the minimum is the width or minor axis diameter w of the particle, in the direction perpendicular to the two parallel lines. When the distance between the two parallel lines is the length of the particle or the major axis diameter l, and the distance when the particle is sandwiched between the planes parallel to the maximum stable surface is the particle height h, l> w ≧ h Say what you meet. The major axis diameter, minor axis diameter, and height can be determined from an arithmetic average value of about 1000 particles of primary particles from an electron micrograph. The size of the titanium oxide having an anisotropic shape used in the present invention, more preferably the range BET specific surface area of about 10 to 200 m 2 / g as described above, in the range of about 10 to 100 m 2 / g More preferred is a range of about 30 to 80 m 2 / g. As such anisotropic shaped particles, those having an average major axis diameter in the range of 10 to 500 nm and an average minor axis diameter in the range of 1 to 25 nm are preferable, and among them, the axial ratio (average major axis diameter / What is called spindle-shaped particles, rod-shaped particles, and needle-like particles having an average minor axis diameter of 1.5 or more is preferable, and the axial ratio is more preferably in the range of 1.5 to 10, and more preferably 2 to 7. It is a range.
また、酸化チタンとオキシ水酸化鉄とを含有した光触媒はアルカリ金属元素及び／またはアルカリ土類金属元素を含有していると、優れた光触媒活性を有することができるため好ましい。アルカリ金属元素、アルカリ土類金属元素を、酸化チタン粒子の表面に有しても、先に記載の通り内部に含有してもよく、さらにオキシ水酸化鉄の内部に含有していても、オキシ水酸化鉄の表面に有していても良く、あるいは、これらから選択されるいずれか二ヶ所以上に有していても良い。特に、酸化チタンの内部及び／または表面に有していると、オキシ水酸化鉄を強固に担持することができるなど優れた光触媒活性を有することができるため好ましい。また、酸化チタンの一部がチタン酸アルカリ金属、チタン酸アルカリ土類金属の複合酸化物であっても良い。アルカリ金属元素としては、ナトリウム、カリウム、リチウム等が、アルカリ土類金属元素としては、カルシウム、マグネシウム、バリウム、ストロンチウム、ベリリウム等が挙げられる。中でもナトリウムは４００〜５００ｎｍの波長の光を吸収するオキシ水酸化鉄を生成し易いため好ましい。アルカリ金属元素及び／またはアルカリ土類金属元素の含有量は、オキシ水酸化鉄と酸化チタンの合量に対する酸化物換算（例えば、Ｎａ２Ｏ、Ｋ２Ｏ、Ｌｉ２Ｏ、ＣａＯ、ＭｇＯ、ＢａＯ、ＳｒＯ、ＢｅＯ等）で表すと、０．０１〜３０重量％の範囲が好ましく、０．０５〜１５重量の範囲が更に好ましく、０．０５〜５重量％の範囲が最も好ましい。アルカリ金属元素、アルカリ土類金属元素の含有形態は、イオン、金属、あるいは酸化物、水酸化物、塩化物等の化合物などいずれでも良く制限されない。尚、本発明における化学組成は、オキシ水酸化鉄の含有量等も含めて、全て蛍光Ｘ線による分析値である。 In addition, it is preferable that a photocatalyst containing titanium oxide and iron oxyhydroxide contains an alkali metal element and / or an alkaline earth metal element because it can have excellent photocatalytic activity. An alkali metal element or an alkaline earth metal element may be contained on the surface of the titanium oxide particles, or may be contained inside as described above, and further may be contained inside the iron oxyhydroxide. You may have on the surface of iron hydroxide, or you may have in any two or more places selected from these. In particular, it is preferable to have it inside and / or on the surface of titanium oxide because it can have excellent photocatalytic activity such as being able to firmly support iron oxyhydroxide. Further, a part of titanium oxide may be a composite oxide of alkali metal titanate and alkaline earth metal titanate. Examples of the alkali metal element include sodium, potassium, and lithium, and examples of the alkaline earth metal element include calcium, magnesium, barium, strontium, and beryllium. Among these, sodium is preferable because it easily generates iron oxyhydroxide that absorbs light having a wavelength of 400 to 500 nm. The content of the alkali metal element and / or alkaline earth metal element is an oxide equivalent relative to the total amount of iron oxyhydroxide and titanium oxide (for example, Na 2 O, K 2 O, Li 2 O, CaO, MgO, BaO). , SrO, BeO, etc.) is preferably in the range of 0.01 to 30% by weight, more preferably in the range of 0.05 to 15% by weight, and most preferably in the range of 0.05 to 5% by weight. The form of the alkali metal element or alkaline earth metal element is not limited and may be any of ions, metals, or compounds such as oxides, hydroxides, and chlorides. In addition, all the chemical compositions in this invention are analysis values by fluorescent X-rays including the content of iron oxyhydroxide and the like.
次に、少なくともオキシ水酸化鉄と酸化チタンを含む本発明の光触媒を製造するには、（ａ）予め製造したオキシ水酸化鉄と酸化チタンとをヘンシェルミキサー、レディゲミキサー、アイリッヒミキサー、ライカイ機等の混合機、乳鉢・乳棒等を用いた混合手段、ボールミル、コロイドミル等の粉砕混合機を用いて混合する方法またはオキシ水酸化鉄と酸化チタンを懸濁状態で撹拌機等を用いて混合する方法、（ｂ）チタン化合物と鉄化合物の混合液と、後述の塩基性化合物とを混合して中和し、反応させて、オキシ水酸化鉄と酸化チタンの両方を析出させる方法、（ｃ）予め製造した酸化チタンの懸濁液に鉄化合物を添加し反応させて、酸化チタンの存在下にオキシ水酸化鉄を生成させる方法、（ｄ）予め製造したオキシ水酸化鉄の懸濁液にチタン化合物を添加し反応させて、オキシ水酸化鉄の存在下に酸化チタンを生成させる方法などを用いることができる。これらの方法の際に、必要に応じて酸化亜鉛、硫化カドミウムなどの光触媒性物質、各種吸着剤などを含ませても良い。 Next, in order to produce the photocatalyst of the present invention containing at least iron oxyhydroxide and titanium oxide, (a) iron oxyhydroxide and titanium oxide produced in advance are combined with a Henschel mixer, a Redige mixer, an Eirich mixer, and a Leicai. A mixing device such as a mortar, a mixing means using a mortar or pestle, a method of mixing using a pulverizing mixer such as a ball mill or a colloid mill, or a stirrer or the like in a suspended state of iron oxyhydroxide and titanium oxide A method of mixing, (b) a method of precipitating both iron oxyhydroxide and titanium oxide by mixing and neutralizing a mixed liquid of a titanium compound and an iron compound and a basic compound described later, c) A method in which an iron compound is added to and reacted with a suspension of titanium oxide produced in advance to produce iron oxyhydroxide in the presence of titanium oxide, (d) a suspension of iron oxyhydroxide produced in advance. By adding a titanium compound reaction, and a method of producing titanium oxide in the presence of iron oxyhydroxide it can be used. In these methods, photocatalytic substances such as zinc oxide and cadmium sulfide, various adsorbents, and the like may be included as necessary.
オキシ水酸化鉄を予め製造するには、硫酸第一鉄、硝酸第一鉄、塩化第一鉄などの第一鉄化合物の溶液に水酸化ナトリウム、水酸化カリウム、アンモニア、アミン、炭酸ナトリウムなどの塩基性化合物を添加し第一鉄化合物の一部分あるいは全部を中和して、次いで、ｐＨを調整しながら空気、酸素などのガスを吹き込んで酸化する方法、硫酸第二鉄、硝酸第二鉄、塩化第二鉄などの第二鉄化合物の溶液に、水酸化ナトリウム、水酸化カリウム、アンモニア、アミン、炭酸ナトリウムなどの塩基性化合物を添加し第二鉄化合物を例えば１０〜７０℃程度の温度で中和した後熟成処理あるいは加熱処理または水熱処理する方法など公知の方法を用いることができる。塩基性のナトリウム化合物を使用すると、４００〜５００ｎｍの光を吸収するオキシ水酸化鉄を生成し易いため好ましい。この方法における熟成処理は、中和生成物を中和温度を保ったまま一定時間保持してオキシ水酸化鉄を生成させる処理であり、熟成時間は１０分〜５時間程度が適当である。加熱処理は、中和生成物を媒液中５０〜２００℃程度の範囲で、より好ましくは７０〜１００℃程度の範囲で加熱してオキシ水酸化鉄を生成させる処理であり、加熱時間は１０分〜５時間程度が適当である。加熱処理の温度が５０℃より低過ぎると、短時間では脱水が進み難く水酸化第二鉄がオキシ水酸化鉄に十分に変性され難いため好ましくない。水熱処理は、中和生成物をオートクレーブなどの高温高圧装置を用いて１００℃程度以上で、より好ましくは１５０〜２００℃程度の範囲で加熱しその温度に応じた水蒸気圧下でオキシ水酸化鉄を生成する処理であり、加熱時間は１０分〜５時間程度が適当である。水熱処理の温度が２００℃より高過ぎると、脱水が進み過ぎて酸化第二鉄にまで変性され易いため好ましくない。得られたオキシ水酸化鉄には、通常行われる手法で濾別、洗浄、乾燥等の操作を適宜行っても良い。 In order to manufacture iron oxyhydroxide in advance, a solution of ferrous sulfate, ferrous nitrate, ferrous chloride, or other ferrous compound is added to a solution of sodium hydroxide, potassium hydroxide, ammonia, amine, sodium carbonate, etc. A method in which a basic compound is added to neutralize part or all of the ferrous compound and then oxidized by blowing a gas such as air or oxygen while adjusting the pH, ferric sulfate, ferric nitrate, A basic compound such as sodium hydroxide, potassium hydroxide, ammonia, amine or sodium carbonate is added to a solution of a ferric compound such as ferric chloride and the ferric compound is heated at a temperature of about 10 to 70 ° C., for example. After neutralization, a known method such as a ripening treatment, a heat treatment or a hydrothermal treatment can be used. The use of a basic sodium compound is preferable because it easily generates iron oxyhydroxide that absorbs light of 400 to 500 nm. The aging treatment in this method is a treatment in which the neutralized product is maintained for a certain period of time while maintaining the neutralization temperature to produce iron oxyhydroxide, and the aging time is suitably about 10 minutes to 5 hours. The heat treatment is a treatment in which the neutralized product is heated in the range of about 50 to 200 ° C., more preferably in the range of about 70 to 100 ° C. to produce iron oxyhydroxide, and the heating time is 10 About 5 to 5 hours is appropriate. If the temperature of the heat treatment is lower than 50 ° C., dehydration is difficult to proceed in a short time, and ferric hydroxide is not easily modified to iron oxyhydroxide, which is not preferable. In the hydrothermal treatment, the neutralized product is heated at a temperature of about 100 ° C. or higher, more preferably in the range of about 150 to 200 ° C. using a high-temperature and high-pressure apparatus such as an autoclave, and iron oxyhydroxide is added under a water vapor pressure corresponding to the temperature. The heating time is about 10 minutes to 5 hours. If the temperature of the hydrothermal treatment is too high, it is not preferable because dehydration proceeds excessively and it is easily modified to ferric oxide. The obtained iron oxyhydroxide may be appropriately subjected to operations such as filtration, washing, and drying by a conventional method.
酸化チタンを予め製造するには、公知の方法を用いることができ、例えば、（１）塩化チタン等を中和する方法、（２）硫酸チタン、硫酸チタニル等を加熱加水分解する方法、（３）前記（１）、（２）の方法で得た生成物を焼成あるいは水熱処理する方法を用いることができる。また、異方性形状を有する酸化チタンも公知の方法で製造したものを用いることができ、例えば、含水酸化チタンを水酸化ナトリウム、炭酸ナトリウム、シュウ酸ナトリウム等の塩基性ナトリウム化合物で処理した後、塩酸で処理する方法を用いることができる。このような方法で得られた酸化チタンは微粒子であり、所謂紡錘状のものであるため、好ましく用いられる。得られた酸化チタンには、通常行われる手法で濾別、洗浄、乾燥等の操作を適宜行っても良い。 In order to produce titanium oxide in advance, a known method can be used. For example, (1) a method of neutralizing titanium chloride or the like, (2) a method of heating and hydrolyzing titanium sulfate, titanyl sulfate or the like, (3 ) A method of firing or hydrothermally treating the product obtained by the methods (1) and (2) can be used. In addition, titanium oxide having an anisotropic shape can also be produced by a known method, for example, after treating hydrous titanium oxide with a basic sodium compound such as sodium hydroxide, sodium carbonate, sodium oxalate, etc. A method of treating with hydrochloric acid can be used. Titanium oxide obtained by such a method is a fine particle and is preferably used because it has a so-called spindle shape. The obtained titanium oxide may be appropriately subjected to operations such as filtration, washing, and drying by a conventional method.
後述する（Ｂ）の方法で用いるアルカリ金属元素、アルカリ土類金属元素を予め含有する酸化チタンは、前記の方法で得られた酸化チタンまたは以下に記載する酸化チタン前駆体と、アルカリ金属、アルカリ土類金属の水酸化物、炭酸塩、硫酸塩、塩化物、酸化物等とを、好ましくはナトリウム化合物とを混合し、焼成することで得られる。酸化チタン前駆体は、焼成によって酸化チタンとなる化合物を言い、例えば、硫酸チタン、硫酸チタニル、塩化チタン、チタンアルコキシド等が挙げられる。含水酸化チタン、水酸化チタンを焼成して酸化チタンとする場合には、含水酸化チタン、水酸化チタンは酸化チタン前駆体に属する。また、アルカリ金属元素、アルカリ土類金属元素を予め含有する酸化チタンは、上記（１）の方法において、塩化チタンを大過剰のアルカリ金属、アルカリ土類金属の塩基性化合物で中和することで、更に好ましくは、アルカリ金属、アルカリ土類金属の塩基性化合物の溶液中に、塩化チタンを添加し中和することでも得られる。同様に、異方性形状を有する酸化チタンは、含水酸化チタンや塩化チタンを大過剰の塩基性ナトリウム化合物で処理した後、好ましくは、塩基性ナトリウム化合物の溶液中に含水酸化チタンを添加して処理した後、塩酸で処理する方法により得ることができる。この方法で得られた異方性形状を有する酸化チタンでは、ナトリウムはイオンとして粒子内部に含有されていると考えられる。 The titanium oxide previously containing an alkali metal element and an alkaline earth metal element used in the method (B) described later is a titanium oxide obtained by the above method or a titanium oxide precursor described below, an alkali metal, an alkali It can be obtained by mixing an earth metal hydroxide, carbonate, sulfate, chloride, oxide or the like, preferably with a sodium compound, and baking. The titanium oxide precursor refers to a compound that becomes titanium oxide by firing, and examples thereof include titanium sulfate, titanyl sulfate, titanium chloride, and titanium alkoxide. When the hydrous titanium oxide or titanium hydroxide is baked into titanium oxide, the hydrous titanium oxide or titanium hydroxide belongs to the titanium oxide precursor. In addition, titanium oxide containing an alkali metal element or alkaline earth metal element in advance can be obtained by neutralizing titanium chloride with a large excess of alkali metal or alkaline earth metal basic compound in the method (1). More preferably, it can also be obtained by adding titanium chloride to a solution of an alkali metal or alkaline earth metal basic compound to neutralize it. Similarly, titanium oxide having an anisotropic shape is preferably prepared by treating hydrous titanium oxide or titanium chloride with a large excess of basic sodium compound, and then adding hydrous titanium oxide to the solution of the basic sodium compound. After the treatment, it can be obtained by a method of treating with hydrochloric acid. In the titanium oxide having an anisotropic shape obtained by this method, sodium is considered to be contained as ions inside the particles.
本発明の酸化チタンとしては、酸化チタンを予め焼成したものや、酸化チタン前駆体を焼成して得られたものが酸化チタンの結晶性が高く、含有する水酸基や水分の量が適度に減少して光触媒活性が一層向上しているので好ましい。焼成温度は２００〜７００℃の範囲が好ましく、焼成温度がこの範囲より低過ぎると、光触媒活性の改良効果が得られ難いため好ましくなく、この範囲より高過ぎても更なる改良効果が得られ難いばかりでなく、生成または成長した光触媒の粒子間の焼結が生じ易くなるため好ましくない。より好ましい焼成温度の範囲は２００〜６００℃であり、更に好ましい範囲は３００〜６００℃である。焼成時間、焼成雰囲気等の条件は適宜設定することができ、焼成時間としては例えば１〜１０時間程度が適当であり、焼成雰囲気としては空気または酸素含有ガスの雰囲気下あるいは窒素、アルゴン等の不活性ガス雰囲気下で行うのが適当である。 As the titanium oxide of the present invention, those obtained by firing titanium oxide in advance or those obtained by firing a titanium oxide precursor have high crystallinity of titanium oxide, and the amount of hydroxyl groups and moisture contained is reduced appropriately. This is preferable because the photocatalytic activity is further improved. The calcining temperature is preferably in the range of 200 to 700 ° C. If the calcining temperature is lower than this range, it is difficult to obtain the effect of improving the photocatalytic activity, and even if it is higher than this range, it is difficult to obtain a further improving effect. In addition, sintering between the produced or grown photocatalyst particles tends to occur, which is not preferable. A more preferable range of the firing temperature is 200 to 600 ° C, and a further preferable range is 300 to 600 ° C. Conditions such as the firing time and the firing atmosphere can be set as appropriate. The firing time is, for example, about 1 to 10 hours. The firing atmosphere is an air or oxygen-containing gas atmosphere or nitrogen, argon or the like. It is appropriate to carry out in an active gas atmosphere.
本発明では、前記（ｃ）に記載したように予め製造した酸化チタンの懸濁液に鉄化合物を添加し反応させて、酸化チタンの存在下にオキシ水酸化鉄を生成させると、酸化チタンの粒子表面にオキシ水酸化鉄が担持し易く、担持したオキシ水酸化鉄と酸化チタンが相互作用して優れた光触媒活性を発現できるためより好ましい。この方法においてより好ましい方法としては、（Ａ）酸化チタンを含む媒液中で鉄化合物を添加し、酸化あるいは熟成処理、加熱処理または水熱処理して反応させる方法、（Ｂ）アルカリ金属元素及び／またはアルカリ土類金属元素を含有した酸化チタンを用いて鉄化合物と接触させ、酸化チタンから溶出したアルカリ金属元素、アルカリ土類金属元素により鉄化合物を中和し、その中和生成物を酸化あるいは熟成処理、加熱処理または水熱処理して反応させる方法、更に、（Ｃ）媒液中に酸化チタンとアルカリ金属元素及び／またはアルカリ土類金属元素の化合物を含ませた後に、鉄化合物を添加し中和して、その中和生成物を酸化あるいは熟成処理、加熱処理または水熱処理して反応させる方法が挙げられる。（Ｂ）に記載の方法は別に中和剤の塩基性化合物を添加する必要が無く、工程が合理的であり、本発明で最も好ましい方法である。また、（Ｂ）及び（Ｃ）に記載の方法によれば、オキシ水酸化鉄を酸化チタン粒子の表面に担持するとともに、アルカリ金属元素及び／またはアルカリ土類金属元素を含有させることができる。尚、（Ｃ）の方法では媒液に鉄化合物とアルカリ金属元素及び／またはアルカリ土類金属元素を別々に添加しても良く、同時並行的に添加しても良い。 In the present invention, as described in (c) above, when an iron compound is added to and reacted with a titanium oxide suspension prepared in advance to produce iron oxyhydroxide in the presence of titanium oxide, Iron oxyhydroxide is easily supported on the particle surface, and the supported iron oxyhydroxide and titanium oxide can interact with each other to exhibit excellent photocatalytic activity. In this method, a more preferable method is (A) a method in which an iron compound is added in a liquid medium containing titanium oxide and reacted by oxidation or aging treatment, heat treatment or hydrothermal treatment, and (B) an alkali metal element and / or Alternatively, titanium oxide containing an alkaline earth metal element is used to contact the iron compound, the iron compound is neutralized by the alkali metal element or alkaline earth metal element eluted from the titanium oxide, and the neutralized product is oxidized or oxidized. A method of reacting by aging treatment, heat treatment or hydrothermal treatment, and (C) adding an iron compound after adding titanium oxide and an alkali metal element and / or alkaline earth metal element compound in the liquid medium. Examples of the method include neutralizing and reacting the neutralized product by oxidation or aging treatment, heat treatment or hydrothermal treatment. The method described in (B) does not require the addition of a basic compound as a neutralizing agent, and the process is rational, and is the most preferable method in the present invention. Moreover, according to the method as described in (B) and (C), while supporting an iron oxyhydroxide on the surface of a titanium oxide particle, an alkali metal element and / or an alkaline-earth metal element can be contained. In the method (C), an iron compound and an alkali metal element and / or an alkaline earth metal element may be added separately to the liquid medium, or may be added in parallel.
前記の（Ａ）、（Ｂ）、（Ｃ）の方法において、媒液としては、水、アルコール、トルエンなどの無機系、有機系の液を用いることもできるが、工業的には水が取り扱い易く好ましい。鉄化合物として第一鉄化合物を用い、その溶液に水酸化ナトリウム、水酸化カリウム、アンモニア、アミン、炭酸ナトリウムなどの塩基性化合物を添加し第一鉄化合物の一部分あるいは全部を中和して、次いで、ｐＨを調整しながら空気、酸素などのガスを吹き込んで酸化して、酸化チタン粒子に水酸化第二鉄を担持させても良いが、第二鉄化合物を用いると酸化する工程が不要であるため好ましい。水系媒液を用いる場合には、水溶性鉄化合物を用いるのが好ましい。水溶性の第二鉄化合物としては、例えば、硝酸第二鉄、硫酸第二鉄、塩化第二鉄等が挙げられる。アルカリ金属化合物、アルカリ土類金属化合物としては、これらの水酸化物、炭酸塩、硫酸塩、塩化物、酸化物等が挙げられ、本発明で光触媒にはアルカリ金属元素としてナトリウムが含有されているのが好ましいので、ナトリウム化合物を用いるのが好ましい。前記酸化チタンと鉄化合物との接触は、酸化チタン粒子の内部や外部に含有されているアルカリ金属元素、アルカリ土類金属元素が遊離し易くなり、鉄化合物との反応が促進されるので酸性下で行うことが好ましい。媒液のｐＨは３以下にするのが好ましく、２以下であれば更に好ましい。ｐＨ調整には、硫酸、塩酸、硝酸、フッ酸等を用いることができる。 In the methods (A), (B), and (C) described above, as the medium, inorganic, organic liquids such as water, alcohol, and toluene can be used. It is easy and preferable. A ferrous compound is used as the iron compound, and a basic compound such as sodium hydroxide, potassium hydroxide, ammonia, amine, sodium carbonate is added to the solution to neutralize part or all of the ferrous compound, and then In addition, it is possible to oxidize by blowing a gas such as air or oxygen while adjusting the pH, and to support the ferric hydroxide on the titanium oxide particles. However, if a ferric compound is used, a step of oxidizing is unnecessary. Therefore, it is preferable. When using an aqueous medium, it is preferable to use a water-soluble iron compound. Examples of the water-soluble ferric compound include ferric nitrate, ferric sulfate, and ferric chloride. Examples of the alkali metal compound and alkaline earth metal compound include these hydroxides, carbonates, sulfates, chlorides, oxides, and the like. In the present invention, the photocatalyst contains sodium as an alkali metal element. Therefore, it is preferable to use a sodium compound. The contact between the titanium oxide and the iron compound is easy to liberate alkali metal elements and alkaline earth metal elements contained inside and outside of the titanium oxide particles, and the reaction with the iron compound is promoted. It is preferable to carry out with. The pH of the liquid medium is preferably 3 or less, more preferably 2 or less. For pH adjustment, sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid, or the like can be used.
このようにして得られた酸化チタンとオキシ水酸化鉄を含有した生成物を粉体とする場合は、通常行われる手法で濾別、洗浄、乾燥等の操作を適宜行っても良く、必要に応じて粉砕を行っても良い。乾燥は、オキシ水酸化鉄が酸化第二鉄に変性しないような温度で行い、例えば２００℃以下の温度で行うのが好ましい。濾別、洗浄する際には、媒液のｐＨを中性付近に、好ましくはｐＨを７前後に調整した後に行うと、酸化チタンが凝集して洗浄性が向上するので好ましいが、媒液中に未反応の鉄化合物が存在すると水酸化鉄が析出するため、予め濾別、洗浄して未反応の鉄化合物を取り除いた後に媒液に再分散させ、改めて媒液のｐＨを中性付近に調整し、濾別し、洗浄するのが好ましい。中和剤には、水酸化物、炭酸塩等の塩基性アルカリ金属化合物、塩基性アルカリ土類金属化合物や、アンモニア、アミン等を用いることができる。再分散に用いる媒液も、水が好ましい。 When the product containing titanium oxide and iron oxyhydroxide obtained in this way is used as a powder, operations such as filtration, washing, and drying may be appropriately performed by a usual method. You may grind | pulverize according to it. Drying is performed at a temperature at which the iron oxyhydroxide does not denature into ferric oxide, and is preferably performed at a temperature of 200 ° C. or lower, for example. When filtering and washing, it is preferable to adjust the pH of the liquid medium to near neutral, preferably after adjusting the pH to around 7, because the titanium oxide aggregates to improve the washing performance. If there is an unreacted iron compound in the solution, iron hydroxide will precipitate, so it is filtered and washed in advance to remove the unreacted iron compound and then redispersed in the medium. It is preferred to prepare, filter and wash. As the neutralizing agent, basic alkali metal compounds such as hydroxides and carbonates, basic alkaline earth metal compounds, ammonia, amines and the like can be used. The medium used for redispersion is also preferably water.
本発明の光触媒を、光触媒反応に実際に用いる場合、必要に応じて、基材に固定させたり、光触媒を成形・造粒して成形体として用いるのが便利である。基材としては例えば、金属、タイル、ホーロー、セメント、コンクリート、ガラス、プラスチック、繊維、木材、紙などの種々の材質で形成されたものであり、その形状としては板状、波板状、ハニカム状、球状、曲面状など種々の形状のものを用いることができる。 When the photocatalyst of the present invention is actually used for a photocatalytic reaction, it is convenient to fix it to a base material as necessary, or to form and granulate the photocatalyst to be used as a molded body. The base material is formed of various materials such as metal, tile, enamel, cement, concrete, glass, plastic, fiber, wood, paper, etc., and the shape is plate, corrugated, honeycomb Various shapes such as a shape, a spherical shape, and a curved shape can be used.
基材に光触媒を固定するには、前記光触媒を光触媒コート剤とし、このコート剤を基材表面に塗布あるいは吹きつけた後、乾燥または焼成する方法を用いることができる。光触媒コート剤には少なくともバインダーが含まれ、バインダーとしては、無機系樹脂、有機系樹脂を用いることができ、光触媒反応により分解され難いバインダー、例えば、重合性ケイ素化合物、セメント、コンクリート、石膏、シリコーン樹脂、フッ素樹脂などが好ましく、中でも重合性ケイ素化合物は耐久性が高く、比較的取扱が容易で汎用性が高いので好ましい。重合性ケイ素化合物としては、例えば、加水分解性シランまたはその加水分解生成物またはその部分縮合物、水ガラス、コロイダルシリカ、オルガノポリシロキサン等が挙げられ、これらの中の１種を用いても、２種以上を混合して用いても良い。加水分解性シランはアルコキシ基、ハロゲン基等の加水分解性基を少なくとも１個含むもので、中でもアルコキシシランが安定性、経済性の点で望ましく、特にテトラメトキシシラン、テトラエトキシシラン等のテトラアルコキシシランが反応性が高く好ましい。水ガラスとしてはナトリウム−ケイ酸系、カリウム−ケイ酸系、リチウム−ケイ酸系等を用いることができ、中でもナトリウム−ケイ酸系が安定性が高いので好ましい。ナトリウム−ケイ酸系の水ガラスはＮａ２ＯとＳｉＯ２のモル比が２〜４の範囲にあると硬化性が高く、安定性と硬化性とのバランスから前記モル比が３の３号水ガラスが特に好ましい。コロイダルシリカやオルガノポリシロキサンとしては、シラノール基を有するものを用いることができる。コート剤には、更に水や、アルコール類、炭化水素類、エーテル類、エーテルアルコール類、エステル類、エーテルエステル類、ケトン類等の非水溶媒が分散媒として含まれていても良く、バインダーとの相溶性に応じて、これらの１種または２種以上を含む混合溶媒などを適宜選択して用いる。コート剤中の固形分濃度は０．０５〜５０重量％の範囲が好ましく、０．１〜４０重量％の範囲が更に好ましい。光触媒は固形分中に２０〜９５重量％含まれているのが好ましく、４０〜９５重量％の範囲が更に好ましい。 In order to fix the photocatalyst to the substrate, it is possible to use a method in which the photocatalyst is used as a photocatalyst coating agent, and this coating agent is applied or sprayed onto the surface of the substrate and then dried or fired. The photocatalyst coating agent contains at least a binder. As the binder, an inorganic resin or an organic resin can be used, and a binder that is difficult to be decomposed by a photocatalytic reaction, such as a polymerizable silicon compound, cement, concrete, gypsum, silicone Resins, fluororesins, and the like are preferable. Among them, a polymerizable silicon compound is preferable because of its high durability, relatively easy handling, and high versatility. Examples of the polymerizable silicon compound include hydrolyzable silane or a hydrolysis product thereof or a partial condensate thereof, water glass, colloidal silica, organopolysiloxane, and the like. Two or more kinds may be mixed and used. Hydrolyzable silanes contain at least one hydrolyzable group such as an alkoxy group or a halogen group. Among these, alkoxysilanes are desirable in terms of stability and economy, and in particular, tetraalkoxysilanes such as tetramethoxysilane and tetraethoxysilane. Silane is preferred because of its high reactivity. As the water glass, sodium-silicic acid system, potassium-silicic acid system, lithium-silicic acid system and the like can be used. Among them, sodium-silicic acid system is preferable because of high stability. A sodium-silicate-based water glass has high curability when the molar ratio of Na 2 O and SiO 2 is in the range of 2 to 4, and No. 3 water has a molar ratio of 3 from the balance between stability and curability. Glass is particularly preferred. As colloidal silica or organopolysiloxane, those having a silanol group can be used. The coating agent may further contain water, a non-aqueous solvent such as alcohols, hydrocarbons, ethers, ether alcohols, esters, ether esters, ketones, etc. as a dispersion medium. Depending on the compatibility, a mixed solvent containing one or more of these is appropriately selected and used. The solid content concentration in the coating agent is preferably in the range of 0.05 to 50% by weight, more preferably in the range of 0.1 to 40% by weight. The photocatalyst is preferably contained in the solid content in an amount of 20 to 95% by weight, and more preferably in the range of 40 to 95% by weight.
コート剤には、光触媒及びバインダーや、分散媒以外にも、本発明の効果を損ねない範囲で、ｐＨ調整剤、分散剤、消泡剤、乳化剤、着色剤、増量剤、防カビ剤、硬化助剤、増粘剤等の各種添加剤、充填剤等が含まれていても良い。これらの添加剤または充填剤が不揮発性であれば、光触媒作用により分解され難い無機系のものを選択するのが好ましい。 In addition to the photocatalyst and binder and the dispersion medium, the coating agent is a pH adjuster, dispersant, antifoaming agent, emulsifier, colorant, extender, antifungal agent, and curing agent as long as the effects of the present invention are not impaired. Various additives such as auxiliaries and thickeners, fillers and the like may be included. If these additives or fillers are non-volatile, it is preferable to select an inorganic material that is difficult to be decomposed by the photocatalytic action.
本発明の光触媒は、予め分散媒に分散させた分散体とすることもできる。分散体を用いて光触媒コート剤を調製すると、高度の分散性が得られ易くなるので好ましい。あるいは、バインダーを用いず、分散体を適当な濃度に希釈して基材表面に塗布あるいは吹きつけた後、乾燥、焼成して、光触媒を基材に固定することもできる。分散体の分散媒には、コート剤に配合されている分散媒と同種のものか、または相溶性が高いものを選択する。また、分散体には分散剤を配合しても良く、分散媒に応じて分散剤種を適宜選択する。分散剤としては、例えば、（１）界面活性剤（（ａ）アニオン系（カルボン酸塩、硫酸エステル塩、スルホン酸塩、リン酸エステル塩等）、（ｂ）カチオン系（アルキルアミン塩、アルキルアミンの４級アンモニウム塩、芳香族４級アンモニウム塩、複素環４級アンモニウム塩等）、（ｃ）両性（ベタイン型、アミノ酸型、アルキルアミンオキシド、含窒素複素環型等）、（ｄ）ノニオン系（エーテル型、エーテルエステル型、エステル型、含窒素型等）等、（２）シリコーン系分散剤（アルキル変性ポリシロキサン、ポリオキシアルキレン変性ポリシロキサン等）、（３）リン酸塩系分散剤（リン酸ナトリウム、ピロリン酸ナトリウム、オルトリン酸ナトリウム、メタリン酸ナトリウム、トリポリリン酸ナトリウム等）、（４）アルカノールアミン類（アミノメチルプロパノール、アミノメチルプロパンジオール等）等が挙げられる。中でもカルボン酸塩系の界面活性剤が、特に高分子型のものが酸化チタンを高度に分散させることができるので好ましい。具体的には、ポリアクリル酸塩（［ＣＨ２ＣＨ（ＣＯＯＭ）］ｎ：Ｍはアルカリ金属、アルカリ土類金属、アンモニウム等、以下も同様）、アクリル酸塩−アクリルアミドコポリマー（［ＣＨ２ＣＨ（ＣＯＯＭ）］ｎ−［ＣＨ２ＣＨ（ＣＯＮＨ２）］ｍ）、アクリル酸−マレイン酸塩コポリマー（［ＣＨ２ＣＨ（ＣＯＯＨ）］ｎ−［ＣＨ２ＣＨ（ＣＯＯＭ）ＣＨ（ＣＯＯＭ）］ｍ）、エチレン−マレイン酸塩コポリマー（［ＣＨ２ＣＨ２］ｎ−［ＣＨ（ＣＯＯＭ）ＣＨ（ＣＯＯＭ）］ｍ）、オレフィン−マレイン酸塩コポリマー（［ＣＨ２ＣＨ（Ｒ）］ｎ−［ＣＨ（ＣＯＯＭ）ＣＨ（ＣＯＯＭ）］ｍ）、スチレン−マレイン酸塩コポリマー（［ＣＨ２ＣＨ（Ｃ６Ｈ５）］ｎ−［ＣＨ（ＣＯＯＭ）ＣＨ（ＣＯＯＭ）］ｍ）等が挙げられる。分散体中の光触媒の配合量は、５〜９０重量％の範囲が好ましく、１０〜８０重量％の範囲が更に好ましい。また、分散剤の配合量は、光触媒に対し０．０１〜２０重量％の範囲が好ましく、０．０１〜１０重量％の範囲が更に好ましい。 The photocatalyst of the present invention may be a dispersion previously dispersed in a dispersion medium. It is preferable to prepare a photocatalyst coating agent using a dispersion because a high degree of dispersibility is easily obtained. Alternatively, without using a binder, the dispersion can be diluted to an appropriate concentration and applied or sprayed onto the surface of the base material, followed by drying and firing to fix the photocatalyst to the base material. As the dispersion medium of the dispersion, the same kind as the dispersion medium blended in the coating agent or a highly compatible one is selected. Moreover, a dispersing agent may be mix | blended with a dispersion and a dispersing agent seed | species is suitably selected according to a dispersing medium. Examples of the dispersant include (1) surfactants ((a) anionic (carboxylates, sulfates, sulfonates, phosphates, etc.), (b) cationics (alkylamine salts, alkyls). Quaternary ammonium salts, aromatic quaternary ammonium salts, heterocyclic quaternary ammonium salts, etc.), (c) amphoteric (betaine type, amino acid type, alkylamine oxide, nitrogen-containing heterocyclic type, etc.), (d) nonion (2) Silicone-based dispersants (alkyl-modified polysiloxane, polyoxyalkylene-modified polysiloxane, etc.), (3) Phosphate-based dispersants, etc. (ether type, ether ester type, ester type, nitrogen-containing type, etc.) (Sodium phosphate, sodium pyrophosphate, sodium orthophosphate, sodium metaphosphate, sodium tripolyphosphate, etc.), (4) alkano Examples thereof include amines (aminomethyl propanol, aminomethyl propane diol, etc.) Among them, carboxylate surfactants are particularly preferable since they can disperse titanium oxide to a high degree, in particular, polymer type surfactants. Specifically, polyacrylate ([CH 2 CH (COOM)] n : M is alkali metal, alkaline earth metal, ammonium, etc., and the same applies below), acrylate-acrylamide copolymer ([CH 2 CH (COOM) )] n - [CH 2 CH (CONH 2)] m), acrylic acid - maleic acid salt copolymer ([CH 2 CH (COOH) ] n - [CH 2 CH (COOM) CH (COOM)] m), ethylene - maleate copolymer ([CH 2 CH 2] n - [CH (COOM) CH (COOM)] m), olefin Maleate copolymer ([CH 2 CH (R) ] n - [CH (COOM) CH (COOM)] m), a styrene - maleate copolymer ([CH 2 CH (C 6 H 5)] n - [CH (COOM) CH (COOM)] m ), etc. The blending amount of the photocatalyst in the dispersion is preferably in the range of 5 to 90% by weight, more preferably in the range of 10 to 80% by weight. Is preferably in the range of 0.01 to 20% by weight, more preferably in the range of 0.01 to 10% by weight, based on the photocatalyst.
光触媒を成形して用いる場合には、必要に応じて粘土、珪藻土、有機系樹脂、無機系樹脂などのバインダーと混合した後、任意の形状に成形することができる。 When the photocatalyst is formed and used, it can be formed into an arbitrary shape after being mixed with a binder such as clay, diatomaceous earth, an organic resin, or an inorganic resin as necessary.
実施例
次に実施例によって本発明をさらに説明するが、これらは本発明を限定するものではない。
EXAMPLES Next, the present invention will be further described by way of examples, but these examples do not limit the present invention.
参考例１
（１）ＴｉＯ２として２００ｇ／リットルの濃度の四塩化チタン水溶液７００ミリリットルに、Ｎａ２Ｏとして１００ｇ／リットルの濃度の水酸化ナトリウム水溶液を添加した。その後、系のｐＨを７に調整した後、濾過し、濾液の導電率が１００μＳ／ｃｍとなるまで洗浄し、乾燥して酸化チタンを得た。
この酸化チタンは、平均長軸径６４ｎｍ、平均短軸径１３ｎｍ（軸比４．９）、比表面積１６０ｍ２／ｇのルチル型結晶を有する紡錘状二酸化チタンであり、酸化チタン粒子の内部にナトリウムをＮａ２Ｏとして１．７重量％含有していた。
（２）純水０．５リットルに、前記の紡錘状二酸化チタン５０ｇを添加、撹拌して分散液とし、硫酸を用いてｐＨを１に調整した。次に、酸化チタンに対しＦｅ換算で０．２重量％に相当する硝酸第二鉄水溶液を添加、混合して、酸化チタンに含有したナトリウム成分により硝酸第二鉄を中和し、引き続き９０℃で１時間加熱処理を行った。加熱処理後、濾過し、得られた酸化チタン粒子の脱水ケーキを、純水０．５リットルに再分散させた。再分散液のｐＨを、水酸化ナトリウムで７前後になるように中和してから、濾過、洗浄し、１１０℃で１昼夜乾燥した後、ライカイ機にて粉砕し、本発明の光触媒（試料Ａ）を得た。
この試料Ａにおいて、α−オキシ水酸化鉄が酸化チタン粒子表面に担持されていることがメスバウアー分光法による分析で確認された。また、試料Ａはα−オキシ水酸化鉄をＦｅ換算で０．２重量％、ナトリウムをＮａ２Ｏとして１．７重量％含有していた。
Reference example 1
(1) A sodium hydroxide aqueous solution having a concentration of 100 g / liter as Na 2 O was added to 700 ml of a titanium tetrachloride aqueous solution having a concentration of 200 g / liter as TiO 2 . Thereafter, the pH of the system was adjusted to 7, then filtered, washed until the filtrate had a conductivity of 100 μS / cm, and dried to obtain titanium oxide.
This titanium oxide is spindle-shaped titanium dioxide having rutile crystals having an average major axis diameter of 64 nm, an average minor axis diameter of 13 nm (axial ratio of 4.9), and a specific surface area of 160 m 2 / g. In an amount of 1.7% by weight as Na 2 O.
(2) 50 g of the above spindle-shaped titanium dioxide was added to 0.5 liter of pure water, stirred to obtain a dispersion, and the pH was adjusted to 1 using sulfuric acid. Next, a ferric nitrate aqueous solution corresponding to 0.2% by weight in terms of Fe is added to and mixed with titanium oxide, and the ferric nitrate is neutralized with a sodium component contained in titanium oxide. For 1 hour. After the heat treatment, filtration was performed, and the resulting dehydrated cake of titanium oxide particles was redispersed in 0.5 liter of pure water. The pH of the re-dispersed liquid is neutralized with sodium hydroxide so as to be about 7, and then filtered, washed, dried at 110 ° C. for one day and night, and then pulverized with a Reika machine. A) was obtained.
In Sample A, it was confirmed by analysis by Mossbauer spectroscopy that α-iron oxyhydroxide was supported on the surface of the titanium oxide particles. Sample A contained 0.2% by weight of α-iron oxyhydroxide in terms of Fe, and 1.7% by weight of sodium as Na 2 O.
参考例２
参考例１で用いた未焼成の紡錘状二酸化チタンを、３５０℃で５時間焼成し、比表面積は６３ｍ２／ｇ、平均長軸径は３８ｎｍ、平均短軸径は１９ｎｍ（軸比２．０）、ナトリウムの含有量がＮａ２Ｏとして０．２６重量％のルチル型結晶を有する焼成紡錘状二酸化チタン（試料ａ）を得た。
未焼成の紡錘状二酸化チタンに替えて、この焼成紡錘状二酸化チタンを用いた以外は参考例１と同様にして本発明の光触媒（試料Ｂ）を得た。
この試料Ｂにおいて、α−オキシ水酸化鉄が酸化チタン粒子表面に担持されていることがメスバウアー分光法による分析で確認された。また、試料Ｂはα−オキシ水酸化鉄をＦｅ換算で０．１９重量％、ナトリウムをＮａ２Ｏとして０．２６重量％含有していた。
Reference example 2
The unsintered spindle-shaped titanium dioxide used in Reference Example 1 was fired at 350 ° C. for 5 hours, the specific surface area was 63 m 2 / g, the average major axis diameter was 38 nm, and the average minor axis diameter was 19 nm (axial ratio 2.0 ), A calcined spindle-shaped titanium dioxide having a sodium content of 0.26 wt% as Na 2 O (sample a) was obtained.
A photocatalyst (sample B) of the present invention was obtained in the same manner as in Reference Example 1 except that this calcined spindle-shaped titanium dioxide was used in place of unsintered spindle-shaped titanium dioxide.
In sample B, it was confirmed by analysis by Mossbauer spectroscopy that α-iron oxyhydroxide was supported on the surface of the titanium oxide particles. Sample B contained α-iron oxyhydroxide in an amount of 0.19% by weight in terms of Fe and 0.26% by weight of sodium as Na 2 O.
参考例３
（１）８０ｇ／リットルの硫酸チタニルの水溶液１リットルを８５℃の温度に加熱し３時間保持して、硫酸チタニルを加水分解した。このようにして得られた加水分解生成物を濾過し、洗浄し、乾燥して、酸化チタンを得た。この酸化チタンは、アナターゼ型結晶を有する球状酸化チタンであり、平均粒子径４．５ｎｍ、比表面積３２０ｍ２／ｇを有し、アルカリ金属元素及びアルカリ土類金属元素は分析されなかった。
（２）純水０．５リットルに、前記の球状二酸化チタン５０ｇを添加、撹拌して分散液とし、硫酸を用いてｐＨを１に調整した。次に、酸化チタンに対しＦｅ換算で０．２重量％に相当する硝酸第二鉄水溶液と水酸化ナトリウムを添加、混合して、硝酸第二鉄を中和し、引き続き９０℃で１時間加熱処理を行った。加熱処理後、濾過し、得られた酸化チタンの脱水ケーキを、純水０．５リットルに再分散させた。再分散液のｐＨを、水酸化ナトリウムで７前後になるように中和してから、濾過、洗浄し、１１０℃で１昼夜乾燥した後、ライカイ機にて粉砕し、本発明の光触媒（試料Ｃ）を得た。
この試料Ｃは、α−オキシ水酸化鉄が酸化チタン粒子表面に担持されていることがメスバウアー分光法による分析で確認された。また、試料Ｃにはα−オキシ水酸化鉄をＦｅ換算で０．２５重量％含有していたが、ナトリウムなどアルカリ金属元素、アルカリ土類金属元素は分析されなかった。
Reference example 3
(1) One liter of an 80 g / liter aqueous solution of titanyl sulfate was heated to a temperature of 85 ° C. and held for 3 hours to hydrolyze the titanyl sulfate. The hydrolyzed product thus obtained was filtered, washed and dried to obtain titanium oxide. This titanium oxide is a spherical titanium oxide having an anatase type crystal, has an average particle diameter of 4.5 nm, a specific surface area of 320 m 2 / g, and an alkali metal element and an alkaline earth metal element were not analyzed.
(2) 50 g of the above spherical titanium dioxide was added to 0.5 liter of pure water, stirred to obtain a dispersion, and the pH was adjusted to 1 using sulfuric acid. Next, ferric nitrate aqueous solution and sodium hydroxide equivalent to 0.2% by weight in terms of Fe with respect to titanium oxide are added and mixed to neutralize the ferric nitrate, and subsequently heated at 90 ° C. for 1 hour. Processed. After the heat treatment, filtration was performed, and the resulting titanium oxide dehydrated cake was redispersed in 0.5 liters of pure water. The pH of the re-dispersed liquid is neutralized with sodium hydroxide so as to be about 7, and then filtered, washed, dried at 110 ° C. for one day and night, and then pulverized with a Reika machine. C) was obtained.
In Sample C, it was confirmed by analysis by Mossbauer spectroscopy that α-iron oxyhydroxide was supported on the titanium oxide particles. Sample C contained 0.25 wt% of α-iron oxyhydroxide in terms of Fe, but alkali metal elements such as sodium and alkaline earth metal elements were not analyzed.
参考例等１
参考例１で用いた紡錘状二酸化チタンとα−オキシ水酸化鉄（石原産業社製：Ｎ−６００）とをライカイ機を用いて混合して、本発明の光触媒（試料Ｄ）を得た。
この試料Ｄは、α−オキシ水酸化鉄が存在していることがメスバウアー分光法による分析で確認された。また、試料Ｄにはα−オキシ水酸化鉄をＦｅ換算で０．７５重量％、ナトリウムをＮａ２Ｏとして１．１９重量％含有していた。
Reference example 1
The spindle-shaped titanium dioxide used in Reference Example 1 and α-iron oxyhydroxide (manufactured by Ishihara Sangyo Co., Ltd .: N-600) were mixed using a Reika machine to obtain the photocatalyst (sample D) of the present invention.
In Sample D, the presence of α-iron oxyhydroxide was confirmed by analysis by Mössbauer spectroscopy. Sample D contained 0.75% by weight of α-iron oxyhydroxide in terms of Fe and 1.19% by weight of sodium as Na 2 O.
参考例等２
参考例１で用いた紡錘状二酸化チタンの懸濁液とα−オキシ水酸化鉄（石原産業社製：Ｎ−６００）の懸濁液とを撹拌機を備えた容器に入れ混合して、その後、濾過、洗浄し、１１０℃で１昼夜乾燥した後、ライカイ機にて粉砕し、本発明の光触媒（試料Ｅ）を得た。
この試料Ｅは、α−オキシ水酸化鉄が存在していることがメスバウアー分光法による分析で確認された。また、試料Ｅにはα−オキシ水酸化鉄をＦｅ換算で０．７５重量％、ナトリウムをＮａ２Ｏとして１．１９重量％含有していた。
Reference example 2
The spindle-shaped titanium dioxide suspension used in Reference Example 1 and the suspension of α-iron oxyhydroxide (manufactured by Ishihara Sangyo Co., Ltd .: N-600) are placed in a container equipped with a stirrer, and then mixed. After filtering and washing, drying at 110 ° C. for one day and night, the mixture was pulverized with a lykai machine to obtain the photocatalyst (sample E) of the present invention.
In Sample E, the presence of α-iron oxyhydroxide was confirmed by analysis by Mossbauer spectroscopy. Sample E contained 0.75% by weight of α-iron oxyhydroxide in terms of Fe and 1.19% by weight of sodium as Na 2 O.
比較例１
参考例１で用いた紡錘状酸化チタンを比較試料（試料Ｆ）として用いた。
Comparative Example 1
The spindle-shaped titanium oxide used in Reference Example 1 was used as a comparative sample (Sample F).
比較例２
参考例２で用いた焼成紡錘状酸化チタンを比較試料（試料Ｇ）として用いた。
Comparative Example 2
The fired spindle-shaped titanium oxide used in Reference Example 2 was used as a comparative sample (Sample G).
比較例３
参考例３で用いた球状酸化チタンを比較試料（試料Ｈ）として用いた。
Comparative Example 3
The spherical titanium oxide used in Reference Example 3 was used as a comparative sample (Sample H).
比較例４
硝酸第二鉄添加後の加熱処理を行わないこと以外は、参考例２と同様にして光触媒（試料Ｉ）を得た。試料Ｉには、水酸化第二鉄が担持されていることがメスバウアー分光法による分析で確認された。
Comparative Example 4
A photocatalyst (sample I) was obtained in the same manner as in Reference Example 2 except that the heat treatment after addition of ferric nitrate was not performed. Sample I was confirmed to be supported by ferrous hydroxide by analysis by Mossbauer spectroscopy.
比較例５
参考例２で得られた試料Ｂを、空気中３５０℃の温度で１時間加熱して光触媒（試料Ｊ）を得た。試料Ｊには、酸化第二鉄が担持されていることがメスバウアー分光法による分析で確認された。
Comparative Example 5
Sample B obtained in Reference Example 2 was heated in air at a temperature of 350 ° C. for 1 hour to obtain a photocatalyst (Sample J). It was confirmed by analysis by Mossbauer spectroscopy that Sample J supported ferric oxide.
比較例６
参考例等１で用いたα−オキシ水酸化鉄（石原産業社製：Ｎ−６００）を比較試料（Ｋ）として用いた。
Comparative Example 6
The α-iron oxyhydroxide (Ishihara Sangyo Co., Ltd .: N-600) used in Reference Example 1 was used as a comparative sample (K).
評価１：アセトアルデヒド分解活性の評価
参考例１〜３及び参考例等１、２及び比較例１〜６で得られた試料（Ａ〜Ｋ）０．１ｇを６ｃｍφのシャーレに均一に広げた。容量が２リットルのフレキシブルバッグにアセトアルデヒドと合成空気を充填し、アセトアルデヒド濃度が２１０ｐｐｍになるように調整した。５００ミリリットル・セパラブルフラスコ内にシャーレを設置した後、フレキシブルバッグと接続し、ポンプにより３リットル／分の速度で系内のガスを循環し、反応を行った。暗条件にて、吸着平衡に到達させた後（３０分程度）、５７００ルクスの白色蛍光灯で５００時間光照射した。サンプリング口より系内のガスをシリンジにて採取し、アセトアルデヒド濃度をガスクロマトグラフにて測定した。アセトアルデヒド濃度の減少速度定数（ｋ）を下式１で計算し、光触媒活性を評価した。このアセトアルデヒドの分解反応速度定数が大きい程、光触媒活性が優れている。結果を表１に示す。本発明で得られた光触媒は、酸化チタンとオキシ水酸化鉄を含有することにより、白色蛍光灯の光照射下での光触媒活性が高いことがわかった。また、本発明の光触媒は紫外線照射下での光触媒活性も高いことから、紫外光に加えて可視光を有効に利用できるため、優れた光触媒活性を有していることがわかった。
式１：ｌｎ（Ｃ／Ｃｏ）＝−ｋｔ
ｋ ：反応速度定数（ｌ／ｈ）
ｔ ：反応時間（ｈ）
Ｃ ：光照射後のアセトアルデヒド濃度（ｐｐｍ）
Ｃｏ：光照射開始時のアセトアルデヒド濃度（ｐｐｍ）
Evaluation 1: Evaluation of acetaldehyde decomposition activity
0.1 g of the samples (A to K) obtained in Reference Examples 1 to 3 and Reference Examples 1 and 2 and Comparative Examples 1 to 6 were uniformly spread on a 6 cmφ petri dish. A flexible bag having a capacity of 2 liters was filled with acetaldehyde and synthetic air, and the acetaldehyde concentration was adjusted to 210 ppm. A petri dish was placed in a 500 ml separable flask, connected to a flexible bag, and the reaction was carried out by circulating gas in the system at a rate of 3 liters / minute with a pump. After reaching adsorption equilibrium under dark conditions (about 30 minutes), light was irradiated with a white fluorescent lamp of 5700 lux for 500 hours. The gas in the system was collected from the sampling port with a syringe, and the acetaldehyde concentration was measured with a gas chromatograph. The reduction rate constant (k) of the acetaldehyde concentration was calculated by the following formula 1, and the photocatalytic activity was evaluated. The larger the acetaldehyde decomposition reaction rate constant, the better the photocatalytic activity. The results are shown in Table 1. It has been found that the photocatalyst obtained in the present invention contains titanium oxide and iron oxyhydroxide, and thus has high photocatalytic activity under the light irradiation of a white fluorescent lamp. Moreover, since the photocatalyst of the present invention also has high photocatalytic activity under ultraviolet irradiation, it was found that visible light can be used effectively in addition to ultraviolet light, and thus has excellent photocatalytic activity.
Formula 1: In (C / Co) = − kt
k: Reaction rate constant (l / h)
t: reaction time (h)
C: Acetaldehyde concentration after light irradiation (ppm)
Co: Acetaldehyde concentration (ppm) at the start of light irradiation
参考例２、比較例４、５で得られた試料Ｂ、Ｉ、Ｊの反射スペクトルと、参考例２で用いた酸化チタン（試料ａ）の反射スペクトルを４００〜７００ｎｍの波長領域で測定し、各波長での試料Ｂ、Ｉ、Ｊの反射スペクトルから酸化チタン（試料ａ）の反射スペクトルを差し引いて、試料Ｂ、Ｉ、Ｊに含有した鉄化合物の吸収スペクトルを求めた。その結果を図１〜図３に示す。α−オキシ水酸化鉄を担持した試料Ｂは、４００〜５００ｎｍの範囲に高い吸収ピークを有することがわかった。この吸収ピークからオキシ水酸化鉄は白色蛍光灯の光に含まれる４００〜５００ｎｍの波長の光を吸収し、この吸収によって酸化チタンが光触媒活性を発現することがわかった。これらのことから、本発明の光触媒が白色蛍光灯の光に含まれる４００〜５００ｎｍの波長の光を吸収するオキシ水酸化鉄を併用することにより、白色蛍光灯の光照射下での光触媒活性が高いことがわかった。 The reflection spectra of Samples B, I, and J obtained in Reference Example 2 and Comparative Examples 4 and 5 and the reflection spectrum of titanium oxide (Sample a) used in Reference Example 2 were measured in the wavelength region of 400 to 700 nm. The absorption spectrum of the iron compound contained in Samples B, I, and J was determined by subtracting the reflection spectrum of titanium oxide (Sample a) from the reflection spectra of Samples B, I, and J at each wavelength. The results are shown in FIGS. It was found that Sample B carrying α-iron oxyhydroxide had a high absorption peak in the range of 400 to 500 nm. From this absorption peak, it was found that iron oxyhydroxide absorbs light having a wavelength of 400 to 500 nm contained in the light of a white fluorescent lamp, and that titanium oxide exhibits photocatalytic activity by this absorption. From these facts, the photocatalytic activity of the white fluorescent lamp under light irradiation can be obtained by using the photocatalyst of the present invention in combination with iron oxyhydroxide that absorbs light having a wavelength of 400 to 500 nm contained in the light of the white fluorescent lamp. I found it expensive.
参考例１、２で得られた試料Ａ、Ｂを用いて、コロイダルシリカをバインダーに、純水を分散媒に用いてコート剤を調製した。また、純水を分散剤に、ポリアクリル酸塩系高分子を分散剤に用い、分散体を得た。これらのコート剤及び水分散体とし、６ｃｍφのシャーレに滴下し、均一に広げた後１１０℃の温度で１２時間乾燥させ光触媒体を得た。その後、評価１と同様に試験したところ、いずれも白色蛍光灯の光に含まれる４００〜５００ｎｍの波長の光を吸収するオキシ水酸化鉄を併用することにより、白色蛍光灯の光照射下での光触媒活性が高く、安定していることを確認し、しかも、紫外線照射下での光触媒活性も高いことから、紫外光に加えて可視光を有効に利用できるため、優れた光触媒活性を有していることを確認した。 Using the samples A and B obtained in Reference Examples 1 and 2 , a coating agent was prepared using colloidal silica as a binder and pure water as a dispersion medium. In addition, a dispersion was obtained using pure water as a dispersant and a polyacrylate polymer as a dispersant. These coating agents and aqueous dispersions were dropped onto a 6 cmφ petri dish, spread uniformly, and then dried at 110 ° C. for 12 hours to obtain a photocatalyst. Thereafter, when tested in the same manner as in Evaluation 1, all of them were used together with iron oxyhydroxide that absorbs light having a wavelength of 400 to 500 nm contained in the light of the white fluorescent lamp. It has been confirmed that the photocatalytic activity is high and stable, and since the photocatalytic activity under ultraviolet irradiation is also high, since visible light can be used effectively in addition to ultraviolet light, it has excellent photocatalytic activity. I confirmed.
参考例１、２で得られた試料Ａ、Ｂを、粘土を用いて成形・造粒して光触媒成形体としても、白色蛍光灯の光に含まれる４００〜５００ｎｍの波長の光を吸収するオキシ水酸化鉄を併用することにより、白色蛍光灯の光照射下での光触媒活性が高く、安定していることを確認し、しかも、紫外線照射下での光触媒活性も高いことから、紫外光に加えて可視光を有効に利用できるため、優れた光触媒活性を有していることを確認した。 Samples A and B obtained in Reference Examples 1 and 2 were molded and granulated using clay to form a photocatalyst molded body, which also absorbs light having a wavelength of 400 to 500 nm contained in the light of a white fluorescent lamp. By using iron hydroxide together, it is confirmed that the photocatalytic activity under white light irradiation is high and stable, and the photocatalytic activity under ultraviolet irradiation is also high. Thus, it was confirmed that it has excellent photocatalytic activity because visible light can be used effectively.
本発明の光触媒は、白色蛍光灯等の光に含まれる４００〜５００ｎｍの波長の光を吸収するオキシ水酸化鉄を併用することにより、白色蛍光灯等の光照射に対して優れた光触媒活性を有しており、可視光（４００〜８００ｎｍの波長の光）が照射する環境下における浄化材、脱臭材、防汚材、殺菌材、防曇材等として広範囲の用途に利用が可能である。
本発明の好ましい態様は下記のとおりである。
１． 酸化チタンを含む媒液中に、鉄化合物を添加し反応させて、該酸化チタンの粒子表面にオキシ水酸化鉄を担持することを特徴とする光触媒の製造方法。
２． アルカリ金属元素及び／またはアルカリ土類金属元素を含有する酸化チタンを含む媒液中に、鉄化合物を添加し反応させて、該酸化チタンの粒子表面にオキシ水酸化鉄を担持することを特徴とする光触媒の製造方法。
３． 酸化チタンとアルカリ金属及び／またはアルカリ土類金属の化合物を含む媒液中に、鉄化合物を添加し反応させて、該酸化チタンの粒子表面にオキシ水酸化鉄を担持することを特徴とする光触媒の製造方法。
４． 酸化チタンを含む媒液のｐＨを酸性に調整した後、鉄化合物を添加することを特徴とする１〜３のいずれかに記載の光触媒の製造方法。
５． 媒液のｐＨを３以下に調整することを特徴とする４に記載の光触媒の製造方法。
６． 鉄化合物を添加した後、媒液を加熱することを特徴とする１〜３のいずれかに記載の光触媒の製造方法。
７． 加熱温度が５０〜２００℃の範囲であることを特徴とする６に記載の光触媒の製造方法。
８． 異方性形状を有する酸化チタンを用いることを特徴とする１〜３のいずれかに記載の光触媒の製造方法。
９． 酸化チタンまたは酸化チタン前駆体を焼成して得られた酸化チタンを用いることを特徴とする１〜３のいずれかに記載の光触媒の製造方法。
１０． 酸化チタンの粒子表面にオキシ水酸化鉄を担持した光触媒であって、
オキシ水酸化鉄が４００〜５００ｎｍの波長の光を吸収することによって酸化チタンが光触媒活性を発現する光触媒であり、
前記光触媒に４００〜５００ｎｍの波長の光を含む白色蛍光灯の光を照射した際のアセトアルデヒド分解反応速度定数が、同じ条件で測定した前記酸化チタンのアセトアルデヒド分解反応速度定数に対して、２倍以上である光触媒と、バインダーとを少なくとも含む光触媒コート剤。
１１． 酸化チタンの粒子表面にオキシ水酸化鉄を担持した光触媒であって、
オキシ水酸化鉄が４００〜５００ｎｍの波長の光を吸収することによって酸化チタンが光触媒活性を発現する光触媒であり、
前記光触媒に４００〜５００ｎｍの波長の光を含む白色蛍光灯の光を照射した際のアセトアルデヒド分解反応速度定数が、同じ条件で測定した前記酸化チタンのアセトアルデヒド分解反応速度定数に対して、２倍以上である光触媒と、分散媒とを少なくとも含む光触媒分散体。
１２． 酸化チタンの粒子表面にオキシ水酸化鉄を担持した光触媒であって、
オキシ水酸化鉄が４００〜５００ｎｍの波長の光を吸収することによって酸化チタンが光触媒活性を発現する光触媒であり、
前記光触媒に４００〜５００ｎｍの波長の光を含む白色蛍光灯の光を照射した際のアセトアルデヒド分解反応速度定数が、同じ条件で測定した前記酸化チタンのアセトアルデヒド分解反応速度定数に対して、２倍以上である光触媒を少なくとも含む光触媒成形体。
１３． 酸化チタンの粒子表面にオキシ水酸化鉄を担持した光触媒であって、
オキシ水酸化鉄が４００〜５００ｎｍの波長の光を吸収することによって酸化チタンが光触媒活性を発現する光触媒であり、
前記光触媒に４００〜５００ｎｍの波長の光を含む白色蛍光灯の光を照射した際のアセトアルデヒド分解反応速度定数が、同じ条件で測定した前記酸化チタンのアセトアルデヒド分解反応速度定数に対して、２倍以上である光触媒を基材上に固定した光触媒体。
The photocatalyst of the present invention has an excellent photocatalytic activity for light irradiation of a white fluorescent lamp or the like by using iron oxyhydroxide that absorbs light having a wavelength of 400 to 500 nm contained in light of a white fluorescent lamp or the like. It can be used for a wide range of applications as a purifying material, a deodorizing material, an antifouling material, a sterilizing material, an antifogging material and the like in an environment irradiated with visible light (light having a wavelength of 400 to 800 nm).
Preferred embodiments of the present invention are as follows.
1. A method for producing a photocatalyst, wherein an iron compound is added to a liquid medium containing titanium oxide and reacted to carry iron oxyhydroxide on the surface of the titanium oxide particles.
2. It is characterized in that an iron compound is added and reacted in a liquid medium containing titanium oxide containing an alkali metal element and / or an alkaline earth metal element, and iron oxyhydroxide is supported on the surface of the titanium oxide particles. A method for producing a photocatalyst.
3. A photocatalyst characterized in that an iron compound is added and reacted in a liquid medium containing a compound of titanium oxide and an alkali metal and / or alkaline earth metal, and iron oxyhydroxide is supported on the surface of the titanium oxide particles. Manufacturing method.
4). The method for producing a photocatalyst according to any one of 1 to 3, wherein an iron compound is added after adjusting the pH of the liquid medium containing titanium oxide to acidic.
5. 5. The method for producing a photocatalyst according to 4, wherein the pH of the liquid medium is adjusted to 3 or less.
6). 4. The method for producing a photocatalyst according to any one of 1 to 3, wherein the liquid medium is heated after adding the iron compound.
7). The method for producing a photocatalyst according to 6, wherein the heating temperature is in the range of 50 to 200 ° C.
8). 4. The method for producing a photocatalyst according to any one of 1 to 3, wherein titanium oxide having an anisotropic shape is used.
9. 4. The method for producing a photocatalyst according to any one of 1 to 3, wherein titanium oxide obtained by firing titanium oxide or a titanium oxide precursor is used.
10. A photocatalyst having iron oxyhydroxide supported on the surface of titanium oxide particles,
The titanium oxide is a photocatalyst that exhibits photocatalytic activity when iron oxyhydroxide absorbs light having a wavelength of 400 to 500 nm,
The acetaldehyde decomposition reaction rate constant when the photocatalyst is irradiated with light from a white fluorescent lamp containing light having a wavelength of 400 to 500 nm is twice or more the acetaldehyde decomposition reaction rate constant of titanium oxide measured under the same conditions. A photocatalyst coating agent comprising at least a photocatalyst and a binder.
11. A photocatalyst having iron oxyhydroxide supported on the surface of titanium oxide particles,
The titanium oxide is a photocatalyst that exhibits photocatalytic activity when iron oxyhydroxide absorbs light having a wavelength of 400 to 500 nm,
The acetaldehyde decomposition reaction rate constant when the photocatalyst is irradiated with light from a white fluorescent lamp containing light having a wavelength of 400 to 500 nm is twice or more the acetaldehyde decomposition reaction rate constant of titanium oxide measured under the same conditions. A photocatalyst dispersion comprising at least a photocatalyst and a dispersion medium.
12 A photocatalyst having iron oxyhydroxide supported on the surface of titanium oxide particles,
The titanium oxide is a photocatalyst that exhibits photocatalytic activity when iron oxyhydroxide absorbs light having a wavelength of 400 to 500 nm,
The acetaldehyde decomposition reaction rate constant when the photocatalyst is irradiated with light from a white fluorescent lamp containing light having a wavelength of 400 to 500 nm is twice or more the acetaldehyde decomposition reaction rate constant of titanium oxide measured under the same conditions. The photocatalyst molded object which contains at least the photocatalyst which is.
13. A photocatalyst having iron oxyhydroxide supported on the surface of titanium oxide particles,
The titanium oxide is a photocatalyst that exhibits photocatalytic activity when iron oxyhydroxide absorbs light having a wavelength of 400 to 500 nm,
The acetaldehyde decomposition reaction rate constant when the photocatalyst is irradiated with light from a white fluorescent lamp containing light having a wavelength of 400 to 500 nm is twice or more the acetaldehyde decomposition reaction rate constant of titanium oxide measured under the same conditions. A photocatalyst having a photocatalyst fixed on a substrate.
Claims (4)
前記光触媒が、酸化チタンの粒子表面にオキシ水酸化鉄が担持され、オキシ水酸化鉄が４００〜５００ｎｍの波長の光を吸収することによって酸化チタンが光触媒活性を発現する光触媒であり、
４００〜５００ｎｍの波長の光を含む白色蛍光灯の光を照射した際のアセトアルデヒド分解反応速度定数が、同じ条件で測定した前記酸化チタンのアセトアルデヒド分解反応速度定数に対して、２倍以上となる光触媒であることを特徴とする光触媒コート剤。 A photocatalyst coating agent comprising at least a photocatalyst and a binder,
The photocatalyst is a photocatalyst in which iron oxyhydroxide is supported on the particle surface of titanium oxide, and the titanium oxyhydroxide absorbs light having a wavelength of 400 to 500 nm so that the titanium oxide exhibits photocatalytic activity.
A photocatalyst in which the acetaldehyde decomposition reaction rate constant when irradiated with light from a white fluorescent lamp containing light having a wavelength of 400 to 500 nm is at least twice the acetaldehyde decomposition reaction rate constant of titanium oxide measured under the same conditions A photocatalyst coating agent characterized by
前記光触媒が、酸化チタンの粒子表面にオキシ水酸化鉄が担持され、オキシ水酸化鉄が４００〜５００ｎｍの波長の光を吸収することによって酸化チタンが光触媒活性を発現する光触媒であり、
４００〜５００ｎｍの波長の光を含む白色蛍光灯の光を照射した際のアセトアルデヒド分解反応速度定数が、同じ条件で測定した前記酸化チタンのアセトアルデヒド分解反応速度定数に対して、２倍以上となる光触媒であることを特徴とする光触媒分散体。 A photocatalyst dispersion containing at least a photocatalyst and a dispersion medium,
The photocatalyst is a photocatalyst in which iron oxyhydroxide is supported on the particle surface of titanium oxide, and the titanium oxyhydroxide absorbs light having a wavelength of 400 to 500 nm so that the titanium oxide exhibits photocatalytic activity.
A photocatalyst in which the acetaldehyde decomposition reaction rate constant when irradiated with light from a white fluorescent lamp containing light having a wavelength of 400 to 500 nm is at least twice the acetaldehyde decomposition reaction rate constant of titanium oxide measured under the same conditions A photocatalyst dispersion characterized in that
前記光触媒が、酸化チタンの粒子表面にオキシ水酸化鉄が担持され、オキシ水酸化鉄が４００〜５００ｎｍの波長の光を吸収することによって酸化チタンが光触媒活性を発現する光触媒であり、
４００〜５００ｎｍの波長の光を含む白色蛍光灯の光を照射した際のアセトアルデヒド分解反応速度定数が、同じ条件で測定した前記酸化チタンのアセトアルデヒド分解反応速度定数に対して、２倍以上となる光触媒であることを特徴とする光触媒成形体。 A photocatalyst molded body containing at least a photocatalyst,
The photocatalyst is a photocatalyst in which iron oxyhydroxide is supported on the particle surface of titanium oxide, and the titanium oxyhydroxide absorbs light having a wavelength of 400 to 500 nm so that the titanium oxide exhibits photocatalytic activity.
A photocatalyst in which the acetaldehyde decomposition reaction rate constant when irradiated with light from a white fluorescent lamp containing light having a wavelength of 400 to 500 nm is at least twice the acetaldehyde decomposition reaction rate constant of titanium oxide measured under the same conditions The photocatalyst molded object characterized by the above-mentioned.
前記光触媒が、酸化チタンの粒子表面にオキシ水酸化鉄が担持され、オキシ水酸化鉄が４００〜５００ｎｍの波長の光を吸収することによって酸化チタンが光触媒活性を発現する光触媒であり、
４００〜５００ｎｍの波長の光を含む白色蛍光灯の光を照射した際のアセトアルデヒド分解反応速度定数が、同じ条件で測定した前記酸化チタンのアセトアルデヒド分解反応速度定数に対して、２倍以上となる光触媒であることを特徴とする光触媒体。 A photocatalyst having a photocatalyst fixed on a substrate,
The photocatalyst is a photocatalyst in which iron oxyhydroxide is supported on the particle surface of titanium oxide, and the titanium oxyhydroxide absorbs light having a wavelength of 400 to 500 nm so that the titanium oxide exhibits photocatalytic activity.
A photocatalyst in which the acetaldehyde decomposition reaction rate constant when irradiated with light from a white fluorescent lamp containing light having a wavelength of 400 to 500 nm is at least twice the acetaldehyde decomposition reaction rate constant of titanium oxide measured under the same conditions A photocatalyst body characterized by the above.
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| JP6394788B2 (en) | 2015-03-23 | 2018-09-26 | 信越化学工業株式会社 | Visible light responsive photocatalytic titanium oxide fine particle dispersion, method for producing the same, and member having photocatalytic thin film on surface |
| JP6624291B2 (en) | 2016-07-14 | 2019-12-25 | 信越化学工業株式会社 | Interior material having surface layer having visible light responsive photocatalytic activity and method for producing the same |
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| WO2018064747A1 (en) * | 2016-10-04 | 2018-04-12 | Rh-Imaging Systems Inc. | Iron doped titanium dioxide nanocrystals and their use as photocatalysts |
| CN108970613B (en) * | 2018-07-17 | 2020-12-25 | 福州大学 | Iron oxyhydroxide modified titanium dioxide composite photocatalyst and preparation method and application thereof |
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