JP2015131985A - Metal/clay mineral composite nanoparticle, dispersion of metal/clay mineral composite nanoparticle and method for producing them - Google Patents
Metal/clay mineral composite nanoparticle, dispersion of metal/clay mineral composite nanoparticle and method for producing them Download PDFInfo
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- JP2015131985A JP2015131985A JP2014003269A JP2014003269A JP2015131985A JP 2015131985 A JP2015131985 A JP 2015131985A JP 2014003269 A JP2014003269 A JP 2014003269A JP 2014003269 A JP2014003269 A JP 2014003269A JP 2015131985 A JP2015131985 A JP 2015131985A
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- Prior art keywords
- metal
- clay mineral
- dispersion
- mineral composite
- nanocrystal
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- 239000002734 clay mineral Substances 0.000 title claims abstract description 120
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 88
- 239000002184 metal Substances 0.000 title claims abstract description 88
- 239000002105 nanoparticle Substances 0.000 title claims abstract description 86
- 239000002131 composite material Substances 0.000 title claims abstract description 80
- 239000006185 dispersion Substances 0.000 title claims abstract description 71
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 24
- 239000002159 nanocrystal Substances 0.000 claims abstract description 44
- 150000002736 metal compounds Chemical class 0.000 claims abstract description 38
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 22
- 239000011258 core-shell material Substances 0.000 claims abstract description 20
- 229910000510 noble metal Inorganic materials 0.000 claims abstract description 10
- 230000000717 retained effect Effects 0.000 claims description 4
- 239000002612 dispersion medium Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 27
- 239000002082 metal nanoparticle Substances 0.000 abstract description 24
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 35
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 34
- 239000007864 aqueous solution Substances 0.000 description 22
- 239000010931 gold Substances 0.000 description 21
- 238000005259 measurement Methods 0.000 description 21
- 239000002245 particle Substances 0.000 description 13
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 8
- 230000003197 catalytic effect Effects 0.000 description 8
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 7
- 238000013507 mapping Methods 0.000 description 7
- 229910052763 palladium Inorganic materials 0.000 description 7
- 229910052697 platinum Inorganic materials 0.000 description 7
- 238000006722 reduction reaction Methods 0.000 description 7
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 6
- 239000011668 ascorbic acid Substances 0.000 description 6
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- 235000010323 ascorbic acid Nutrition 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 238000000026 X-ray photoelectron spectrum Methods 0.000 description 5
- 238000002474 experimental method Methods 0.000 description 5
- 229910052737 gold Inorganic materials 0.000 description 5
- -1 halide ions Chemical class 0.000 description 5
- 150000002739 metals Chemical class 0.000 description 5
- 229910002093 potassium tetrachloropalladate(II) Inorganic materials 0.000 description 5
- 239000012279 sodium borohydride Substances 0.000 description 5
- 229910000033 sodium borohydride Inorganic materials 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- BTJIUGUIPKRLHP-UHFFFAOYSA-N 4-nitrophenol Chemical compound OC1=CC=C([N+]([O-])=O)C=C1 BTJIUGUIPKRLHP-UHFFFAOYSA-N 0.000 description 4
- 229910020427 K2PtCl4 Inorganic materials 0.000 description 4
- 229910052500 inorganic mineral Inorganic materials 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 239000011707 mineral Substances 0.000 description 4
- 235000010755 mineral Nutrition 0.000 description 4
- 150000002894 organic compounds Chemical class 0.000 description 4
- 238000004736 wide-angle X-ray diffraction Methods 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 description 3
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- ZMANZCXQSJIPKH-UHFFFAOYSA-N Triethylamine Chemical compound CCN(CC)CC ZMANZCXQSJIPKH-UHFFFAOYSA-N 0.000 description 3
- 150000001412 amines Chemical class 0.000 description 3
- 239000003054 catalyst Substances 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 229910017052 cobalt Inorganic materials 0.000 description 3
- 239000010941 cobalt Substances 0.000 description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 3
- XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 description 3
- 239000011734 sodium Substances 0.000 description 3
- PLIKAWJENQZMHA-UHFFFAOYSA-N 4-aminophenol Chemical compound NC1=CC=C(O)C=C1 PLIKAWJENQZMHA-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 2
- NBBJYMSMWIIQGU-UHFFFAOYSA-N Propionic aldehyde Chemical compound CCC=O NBBJYMSMWIIQGU-UHFFFAOYSA-N 0.000 description 2
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 150000001450 anions Chemical class 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000010866 blackwater Substances 0.000 description 2
- HQABUPZFAYXKJW-UHFFFAOYSA-N butan-1-amine Chemical compound CCCCN HQABUPZFAYXKJW-UHFFFAOYSA-N 0.000 description 2
- 235000014113 dietary fatty acids Nutrition 0.000 description 2
- PKRPQASGRXWUOJ-UHFFFAOYSA-L dipotassium;dichloride Chemical compound [Cl-].[Cl-].[K+].[K+] PKRPQASGRXWUOJ-UHFFFAOYSA-L 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000921 elemental analysis Methods 0.000 description 2
- 239000000194 fatty acid Substances 0.000 description 2
- 229930195729 fatty acid Natural products 0.000 description 2
- 150000004665 fatty acids Chemical class 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910021645 metal ion Inorganic materials 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 229920005862 polyol Polymers 0.000 description 2
- 150000003077 polyols Chemical class 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- WGYKZJWCGVVSQN-UHFFFAOYSA-N propylamine Chemical compound CCCN WGYKZJWCGVVSQN-UHFFFAOYSA-N 0.000 description 2
- 229910052707 ruthenium Inorganic materials 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Chemical compound [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 description 2
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
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- 229920003169 water-soluble polymer Polymers 0.000 description 2
- VILCJCGEZXAXTO-UHFFFAOYSA-N 2,2,2-tetramine Chemical compound NCCNCCNCCN VILCJCGEZXAXTO-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- 229910001111 Fine metal Inorganic materials 0.000 description 1
- 241000871495 Heeria argentea Species 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- UEEJHVSXFDXPFK-UHFFFAOYSA-N N-dimethylaminoethanol Chemical compound CN(C)CCO UEEJHVSXFDXPFK-UHFFFAOYSA-N 0.000 description 1
- OPKOKAMJFNKNAS-UHFFFAOYSA-N N-methylethanolamine Chemical compound CNCCO OPKOKAMJFNKNAS-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 229920002873 Polyethylenimine Polymers 0.000 description 1
- FOIXSVOLVBLSDH-UHFFFAOYSA-N Silver ion Chemical compound [Ag+] FOIXSVOLVBLSDH-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- RJDOZRNNYVAULJ-UHFFFAOYSA-L [O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[F-].[F-].[Mg++].[Mg++].[Mg++].[Al+3].[Si+4].[Si+4].[Si+4].[K+] Chemical compound [O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[F-].[F-].[Mg++].[Mg++].[Mg++].[Al+3].[Si+4].[Si+4].[Si+4].[K+] RJDOZRNNYVAULJ-UHFFFAOYSA-L 0.000 description 1
- 238000000862 absorption spectrum Methods 0.000 description 1
- IKHGUXGNUITLKF-XPULMUKRSA-N acetaldehyde Chemical compound [14CH]([14CH3])=O IKHGUXGNUITLKF-XPULMUKRSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 150000001639 boron compounds Chemical class 0.000 description 1
- ZTQSAGDEMFDKMZ-UHFFFAOYSA-N butyric aldehyde Natural products CCCC=O ZTQSAGDEMFDKMZ-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- PTYMQUSHTAONGW-UHFFFAOYSA-N carbonic acid;hydrazine Chemical compound NN.OC(O)=O PTYMQUSHTAONGW-UHFFFAOYSA-N 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 1
- BGORGFZEVHFAQU-UHFFFAOYSA-L cobalt(2+);sulfate;hydrate Chemical compound O.[Co+2].[O-]S([O-])(=O)=O BGORGFZEVHFAQU-UHFFFAOYSA-L 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
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- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- 229910000366 copper(II) sulfate Inorganic materials 0.000 description 1
- CYKLGTUKGYURDP-UHFFFAOYSA-L copper;hydrogen sulfate;hydroxide Chemical compound O.[Cu+2].[O-]S([O-])(=O)=O CYKLGTUKGYURDP-UHFFFAOYSA-L 0.000 description 1
- 229960002887 deanol Drugs 0.000 description 1
- GUJOJGAPFQRJSV-UHFFFAOYSA-N dialuminum;dioxosilane;oxygen(2-);hydrate Chemical compound O.[O-2].[O-2].[O-2].[Al+3].[Al+3].O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O GUJOJGAPFQRJSV-UHFFFAOYSA-N 0.000 description 1
- HPNMFZURTQLUMO-UHFFFAOYSA-N diethylamine Chemical compound CCNCC HPNMFZURTQLUMO-UHFFFAOYSA-N 0.000 description 1
- XPPKVPWEQAFLFU-UHFFFAOYSA-J diphosphate(4-) Chemical compound [O-]P([O-])(=O)OP([O-])([O-])=O XPPKVPWEQAFLFU-UHFFFAOYSA-J 0.000 description 1
- 235000011180 diphosphates Nutrition 0.000 description 1
- WEHWNAOGRSTTBQ-UHFFFAOYSA-N dipropylamine Chemical compound CCCNCCC WEHWNAOGRSTTBQ-UHFFFAOYSA-N 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- KWLMIXQRALPRBC-UHFFFAOYSA-L hectorite Chemical compound [Li+].[OH-].[OH-].[Na+].[Mg+2].O1[Si]2([O-])O[Si]1([O-])O[Si]([O-])(O1)O[Si]1([O-])O2 KWLMIXQRALPRBC-UHFFFAOYSA-L 0.000 description 1
- 229910000271 hectorite Inorganic materials 0.000 description 1
- 150000002429 hydrazines Chemical class 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
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- 150000002466 imines Chemical class 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 229940094522 laponite Drugs 0.000 description 1
- XCOBTUNSZUJCDH-UHFFFAOYSA-B lithium magnesium sodium silicate Chemical compound [Li+].[Li+].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[Na+].[Na+].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].O1[Si](O2)([O-])O[Si]3([O-])O[Si]1([O-])O[Si]2([O-])O3.O1[Si](O2)([O-])O[Si]3([O-])O[Si]1([O-])O[Si]2([O-])O3.O1[Si](O2)([O-])O[Si]3([O-])O[Si]1([O-])O[Si]2([O-])O3.O1[Si](O2)([O-])O[Si]3([O-])O[Si]1([O-])O[Si]2([O-])O3.O1[Si](O2)([O-])O[Si]3([O-])O[Si]1([O-])O[Si]2([O-])O3.O1[Si](O2)([O-])O[Si]3([O-])O[Si]1([O-])O[Si]2([O-])O3 XCOBTUNSZUJCDH-UHFFFAOYSA-B 0.000 description 1
- 239000002609 medium Substances 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 1
- 239000010445 mica Substances 0.000 description 1
- 229910052618 mica group Inorganic materials 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052901 montmorillonite Inorganic materials 0.000 description 1
- DAZXVJBJRMWXJP-UHFFFAOYSA-N n,n-dimethylethylamine Chemical compound CCN(C)C DAZXVJBJRMWXJP-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 238000005580 one pot reaction Methods 0.000 description 1
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- 239000010452 phosphate Substances 0.000 description 1
- 229920000083 poly(allylamine) Polymers 0.000 description 1
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- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 1
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- 229910052703 rhodium Inorganic materials 0.000 description 1
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- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 229910000275 saponite Inorganic materials 0.000 description 1
- 238000001350 scanning transmission electron microscopy Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- CQLFBEKRDQMJLZ-UHFFFAOYSA-M silver acetate Chemical compound [Ag+].CC([O-])=O CQLFBEKRDQMJLZ-UHFFFAOYSA-M 0.000 description 1
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- 150000003379 silver compounds Chemical class 0.000 description 1
- 229940096017 silver fluoride Drugs 0.000 description 1
- REYHXKZHIMGNSE-UHFFFAOYSA-M silver monofluoride Chemical compound [F-].[Ag+] REYHXKZHIMGNSE-UHFFFAOYSA-M 0.000 description 1
- 229910001961 silver nitrate Inorganic materials 0.000 description 1
- KKKDGYXNGYJJRX-UHFFFAOYSA-M silver nitrite Chemical compound [Ag+].[O-]N=O KKKDGYXNGYJJRX-UHFFFAOYSA-M 0.000 description 1
- 229910001923 silver oxide Inorganic materials 0.000 description 1
- CHACQUSVOVNARW-LNKPDPKZSA-M silver;(z)-4-oxopent-2-en-2-olate Chemical compound [Ag+].C\C([O-])=C\C(C)=O CHACQUSVOVNARW-LNKPDPKZSA-M 0.000 description 1
- XAYJXAUUXJTOSI-UHFFFAOYSA-M silver;2,2,3,3,3-pentafluoropropanoate Chemical compound [Ag+].[O-]C(=O)C(F)(F)C(F)(F)F XAYJXAUUXJTOSI-UHFFFAOYSA-M 0.000 description 1
- LMEWRZSPCQHBOB-UHFFFAOYSA-M silver;2-hydroxypropanoate Chemical compound [Ag+].CC(O)C([O-])=O LMEWRZSPCQHBOB-UHFFFAOYSA-M 0.000 description 1
- CLDWGXZGFUNWKB-UHFFFAOYSA-M silver;benzoate Chemical compound [Ag+].[O-]C(=O)C1=CC=CC=C1 CLDWGXZGFUNWKB-UHFFFAOYSA-M 0.000 description 1
- 239000001509 sodium citrate Substances 0.000 description 1
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
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- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- AZJYLVAUMGUUBL-UHFFFAOYSA-A u1qj22mc8e Chemical compound [F-].[F-].[F-].[F-].[F-].[F-].[F-].[F-].[F-].[F-].[F-].[F-].[F-].[F-].[F-].[F-].[F-].[F-].[Na+].[Na+].[Na+].[Na+].[Na+].[Na+].[Na+].[Na+].[Na+].[Na+].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].O=[Si]=O.O=[Si]=O.O=[Si]=O.O1[Si](O2)([O-])O[Si]3([O-])O[Si]1([O-])O[Si]2([O-])O3.O1[Si](O2)([O-])O[Si]3([O-])O[Si]1([O-])O[Si]2([O-])O3.O1[Si](O2)([O-])O[Si]3([O-])O[Si]1([O-])O[Si]2([O-])O3.O1[Si](O2)([O-])O[Si]3([O-])O[Si]1([O-])O[Si]2([O-])O3.O1[Si](O2)([O-])O[Si]3([O-])O[Si]1([O-])O[Si]2([O-])O3.O1[Si](O2)([O-])O[Si]3([O-])O[Si]1([O-])O[Si]2([O-])O3 AZJYLVAUMGUUBL-UHFFFAOYSA-A 0.000 description 1
- 238000002525 ultrasonication Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
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- 229910052726 zirconium Inorganic materials 0.000 description 1
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Abstract
Description
本発明は、金属ナノ粒子、その分散液及びそれらの製造方法に関する。 The present invention relates to metal nanoparticles, a dispersion thereof, and a production method thereof.
金属ナノ粒子は、その微小粒径に起因してバルク態と異なる多くの特性を示すことから、触媒、導電材料を始めとした各種分野で幅広い利用が検討されている。しかし、金属ナノ粒子の粒径をｎｍレベルの小粒径でできるだけ均質に且つ安価に合成すること、及び、金属ナノ粒子は活性が非常に高く粒子同士の不均一な凝集が生じやすいことから、安定した金属ナノ粒子分散液を調製することが広く求められてきた。 Since metal nanoparticles exhibit many characteristics different from the bulk state due to their fine particle diameter, they are being studied for wide use in various fields including catalysts and conductive materials. However, since the metal nanoparticles have a particle size as small as nm and can be synthesized as homogeneously and inexpensively as possible, and metal nanoparticles are very active and tend to cause non-uniform aggregation between particles. There has been a widespread need to prepare stable metal nanoparticle dispersions.
例えば、金属ナノ粒子の製造において、金属塩の溶液に還元剤を一挙に添加する従来の生成方法では金属粒子の核形成ならびにその成長の制御が容易でなく、ｎｍレベルの粒子径のそろった均整な粒子を得ることが難しかった。これに対して、ポリオールを用いて還元した後、水溶性高分子を用いて分散性をあげる方法（非特許文献１）、連続フロー方式での製造方法（特許文献１）、ハロゲン化物イオンの存在下で還元させる方法（特許文献２）、異種金属を共存させる方法（特許文献３）などが提案されている。 For example, in the production of metal nanoparticles, the conventional production method in which a reducing agent is added all at once to a metal salt solution is not easy to control the nucleation and growth of metal particles, and the particle size is evenly aligned at the nm level. It was difficult to obtain fine particles. On the other hand, after reduction using a polyol, a method of increasing dispersibility using a water-soluble polymer (Non-patent Document 1), a production method using a continuous flow system (Patent Document 1), presence of halide ions There are proposed a method of reducing under pressure (Patent Document 2), a method of coexisting different metals (Patent Document 3), and the like.
一方、金属ナノ粒子が不均一に凝集したり沈殿したりするとナノ粒子としての性能が十分に発揮できないことに対する、分散液中又は再分散液中での金属ナノ粒子の安定な均一分散の達成に関しては、例えば、金属ナノ粒子の表面を特定の有機化合物で被覆する方法（特許文献４）、脂肪酸金属塩を形成させた後、二段階の置換を経て炭素鎖８〜２０のアミンと原料由来の脂肪酸で金属ナノ粒子の表面を被覆する方法（特許文献５）、一端保護した有機化合物を別の有機化合物保護剤に置換する方法（特許文献６）、ポリエチレンイミンとポリエチレングリコールを含む高分子化合物の存在下で銀化合物を還元して銀ナノ粒子を製造する方法（特許文献７）、カルボキシル基を有する有機化合物からなる保護材で金属ナノ粒子表面を被覆する方法（特許文献８）などが提案されている。また、本発明者は、金属ナノ粒子及びその安定した分散液を得るために、層状剥離した無機層状鉱物の存在下で金属化合物を還元させる方法（特許文献９）を報告している。 On the other hand, regarding the achievement of stable and uniform dispersion of metal nanoparticles in a dispersion or redispersion liquid, the performance as a nanoparticle cannot be sufficiently exerted when metal nanoparticles aggregate or precipitate unevenly. Is, for example, a method of coating the surface of metal nanoparticles with a specific organic compound (Patent Document 4), after forming a fatty acid metal salt, followed by two-stage substitution and derived from amines and raw materials of carbon chains 8 to 20 A method of coating the surface of metal nanoparticles with a fatty acid (Patent Document 5), a method of replacing a partially protected organic compound with another organic compound protective agent (Patent Document 6), and a polymer compound containing polyethyleneimine and polyethylene glycol A method for producing silver nanoparticles by reducing a silver compound in the presence (Patent Document 7), and coating a metal nanoparticle surface with a protective material made of an organic compound having a carboxyl group Such method (Patent Document 8) it has been proposed. In addition, the present inventor has reported a method (Patent Document 9) in which a metal compound is reduced in the presence of a layered exfoliated inorganic layered mineral in order to obtain metal nanoparticles and a stable dispersion thereof.
一方、近年、複数の金属を用いた金属ナノ粒子、特にコアシェル構造などの制御された構造を有するナノ粒子は優れた触媒特性や光特性などを示す可能性から大きな注目を浴びている（非特許文献２）。製造法としても、複数の金属からなる金属ナノ粒子の分散性を向上させるためやコアシェル構造などの構造を構築させるための方法が提案されている（特許文献１０〜特許文献１３）。しかし、いずれも複雑な工程を要したり、高価な装置を用いたりして、簡便にして高効率な製造法は知られていない。このように、複数の金属ナノ結晶からなる金属ナノ粒子の内部構造を制御して合成し、且つ、分散性に優れたその金属ナノ粒子の分散液を得る簡便な方法はなく、これらの開発が求められていた。
On the other hand, in recent years, metal nanoparticles using a plurality of metals, particularly nanoparticles having a controlled structure such as a core-shell structure, have attracted a great deal of attention due to the possibility of exhibiting excellent catalytic properties, optical properties, etc. Reference 2). As a manufacturing method, methods for improving the dispersibility of metal nanoparticles composed of a plurality of metals and for constructing a structure such as a core-shell structure have been proposed (
本発明が解決しようとする課題は、内部構造の制御された複数の金属ナノ結晶からなる金属ナノ粒子、及び分散安定性に優れたその分散液、及びそれらの製造方法を提供することにある。 The problem to be solved by the present invention is to provide metal nanoparticles composed of a plurality of metal nanocrystals whose internal structure is controlled, a dispersion thereof excellent in dispersion stability, and a method for producing them.
本発明者は、上記課題を解決すべく鋭意研究に取り組んだ結果、層状剥離した粘土鉱物、特に層状剥離した水膨潤性粘土鉱物の水分散液に、貴金属種を含む複数の金属化合物を同時に添加した後、還元剤を添加し、それを室温で保持する方法、または、粘土鉱物の水分散液に一つの金属化合物を添加し分散させた後、還元剤を添加し、一定時間後に更に他の金属化合物を添加し室温で保持する方法によって、複数の金属ナノ結晶からなり、且つ、コアシェル構造などの制御された内部構造を有する金属／粘土鉱物複合ナノ粒子が得られること、また、極めて安定した金属／粘土鉱物複合ナノ粒子分散液が得られることを発見したことに基づき、本発明を完成するに至った。 As a result of diligent research to solve the above problems, the present inventor simultaneously added a plurality of metal compounds containing a noble metal species to an aqueous dispersion of a layered exfoliated clay mineral, particularly a layered exfoliated water-swelling clay mineral. After that, a reducing agent is added and kept at room temperature, or after one metal compound is added and dispersed in an aqueous dispersion of clay mineral, a reducing agent is added, and after another period of time, another reducing agent is added. By adding a metal compound and keeping it at room temperature, it is possible to obtain metal / clay mineral composite nanoparticles composed of a plurality of metal nanocrystals and having a controlled internal structure such as a core-shell structure, and extremely stable. Based on the discovery that a metal / clay mineral composite nanoparticle dispersion can be obtained, the present invention has been completed.
即ち、本発明は、コアシェル構造を形成している複数の金属ナノ結晶及び層状剥離した粘土鉱物からなる金属／粘土鉱物複合ナノ粒子を提供する。 That is, the present invention provides metal / clay mineral composite nanoparticles comprising a plurality of metal nanocrystals forming a core-shell structure and a layered exfoliated clay mineral.
また、本発明は、コアシェル構造の最外層が微細な凹凸構造を有する金属／粘土鉱物複合ナノ粒子を提供する。 The present invention also provides metal / clay mineral composite nanoparticles in which the outermost layer of the core-shell structure has a fine uneven structure.
また、本発明は、複数金属ナノ結晶の少なくとも一種が貴金属ナノ結晶である金属／粘土鉱物複合ナノ粒子を提供する。 The present invention also provides metal / clay mineral composite nanoparticles in which at least one of a plurality of metal nanocrystals is a noble metal nanocrystal.
また、本発明は、粘土鉱物が水中で層状剥離可能な水膨潤性粘土鉱物である金属／粘土鉱物複合ナノ粒子を提供する。 The present invention also provides metal / clay mineral composite nanoparticles in which the clay mineral is a water-swellable clay mineral that can be layered and peeled off in water.
また、本発明は、金属／粘土鉱物複合ナノ粒子と層状剥離した粘土鉱物と分散媒体を含んでなる金属／粘土鉱物複合ナノ粒子分散液を提供する。 The present invention also provides a metal / clay mineral composite nanoparticle dispersion comprising a metal / clay mineral composite nanoparticle, a layered exfoliated clay mineral, and a dispersion medium.
また、本発明は、層状剥離した粘土鉱物を含む水分散液に、複数の金属化合物を同時に添加した後、還元剤を添加し、それらを保持することを特徴とする金属／粘土鉱物複合ナノ粒子及びその分散液の製造方法を提供する。 The present invention also relates to a metal / clay mineral composite nanoparticle characterized in that a plurality of metal compounds are simultaneously added to an aqueous dispersion containing a layered exfoliated clay mineral, and then a reducing agent is added and retained. And a method for producing the dispersion.
また、本発明は、層状剥離した粘土鉱物を含む水分散液に、少なくとも一種の金属化合物を添加した後、還元剤を添加し、その後、時間をおいて他の金属化合物を添加し、更にそれらを保持することを特徴とする金属／粘土鉱物複合ナノ粒子及びその分散液の製造方法を提供する。
また、本発明は、還元剤を添加した後、超音波をかけることを特徴とする金属／粘土鉱物複合ナノ粒子及びその分散液の製造方法を提供する。
更に、本発明は、金属化合物を還元するための保持温度が５〜５０℃であることを特徴とする金属／粘土鉱物複合ナノ粒子及びその分散液の製造方法を提供する。
In addition, the present invention adds at least one metal compound to an aqueous dispersion containing a clay mineral that has been exfoliated in layers, then adds a reducing agent, and then adds another metal compound over time, and further adds them. A metal / clay mineral composite nanoparticle and a method for producing a dispersion thereof are provided.
In addition, the present invention provides a method for producing metal / clay mineral composite nanoparticles and a dispersion thereof characterized by applying ultrasonic waves after adding a reducing agent.
Furthermore, the present invention provides a method for producing metal / clay mineral composite nanoparticles and a dispersion thereof, wherein the holding temperature for reducing the metal compound is 5 to 50 ° C.
本発明によると、貴金属を含む複数の金属からなり、内部構造がコアシェル型に制御された金属／粘土鉱物複合ナノ粒子が得られること、また、最表面部に微細な凹凸構造を有するものが得られること、更に、分散性・分散安定性に優れた金属／粘土鉱物複合ナノ粒子分散液が得られることなどが達成され、例えば、優れた触媒性能や導電性などを有する材料として用いられる。 According to the present invention, it is possible to obtain metal / clay mineral composite nanoparticles composed of a plurality of metals including a noble metal and whose inner structure is controlled to a core-shell type, and those having a fine concavo-convex structure on the outermost surface portion. In addition, it is possible to obtain a metal / clay mineral composite nanoparticle dispersion having excellent dispersibility and dispersion stability. For example, it can be used as a material having excellent catalytic performance and conductivity.
本発明における金属／粘土鉱物複合ナノ粒子は、２種またはそれ以上の複数の金属ナノ結晶からなることが必須である。金属の種類は必ずしも限定されないが、少なくとも１種は貴金属であるものがより好ましく用いられる、特に好ましくは、ナノ粒子の最外層に貴金属があるものである。貴金属としては、例えば、金、銀、白金、パラジウム、ロジウム、イリジウム、ルテニウムなどが挙げられ、特に好ましくは、金、白金、パラジウムである。その他の金属としては、銅、ニッケル、鉄、コバルト、アルミニウム、亜鉛、クロム、鉄、モリブデン、ジルコニウム、ルテニウム、タンタル、水銀、インジウム、スズ、鉛、タングステンなどがあげられ、より好ましくは、鉄、ニッケル、銅、コバルトである。 It is essential that the metal / clay mineral composite nanoparticles in the present invention consist of two or more metal nanocrystals. The kind of metal is not necessarily limited, but at least one kind is preferably a noble metal, and more preferably, a metal having a noble metal in the outermost layer of the nanoparticles. Examples of the noble metal include gold, silver, platinum, palladium, rhodium, iridium, ruthenium and the like, and gold, platinum, and palladium are particularly preferable. Examples of other metals include copper, nickel, iron, cobalt, aluminum, zinc, chromium, iron, molybdenum, zirconium, ruthenium, tantalum, mercury, indium, tin, lead, tungsten, and more preferably iron, Nickel, copper and cobalt.
金属／粘土鉱物複合ナノ粒子の粒子径としては、ナノ粒子としての特徴を有するのであれば特に限定されるものではないが、金属／粘土鉱物複合ナノ粒子分散液とした場合に良好な分散安定性を有するためには、本発明の金属ナノ粒子の平均粒子径は１〜３００ｎｍの範囲であることが好ましく、より好ましくは５〜１５０ｎｍの範囲、特に好ましくは１０〜１００ｎｍの範囲である。また、形状は一般に球状であるが、本発明における製造条件を制御することで、異型形状、瓢箪状、ロッド状、リボン状などの形状にすることも可能である。 The particle diameter of the metal / clay mineral composite nanoparticles is not particularly limited as long as they have the characteristics of nanoparticles, but good dispersion stability when a metal / clay mineral composite nanoparticle dispersion is used. In order to have this, it is preferable that the average particle diameter of the metal nanoparticle of this invention is the range of 1-300 nm, More preferably, it is the range of 5-150 nm, Most preferably, it is the range of 10-100 nm. In addition, the shape is generally spherical, but by controlling the manufacturing conditions in the present invention, it is possible to obtain a shape such as an irregular shape, a saddle shape, a rod shape, or a ribbon shape.
本発明における金属／粘土鉱物複合ナノ粒子は、複数の金属ナノ結晶と層状剥離した粘土鉱物が含まれていることが必須である。金属／粘土鉱物複合ナノ粒子中の金属ナノ結晶含有量は、安定した金属／粘土鉱物複合ナノ粒子又はその分散液が得られれば良く、目的に応じて広い範囲から選択される。 The metal / clay mineral composite nanoparticles in the present invention must contain a plurality of metal nanocrystals and layered exfoliated clay minerals. The metal nanocrystal content in the metal / clay mineral composite nanoparticles may be selected from a wide range according to the purpose as long as stable metal / clay mineral composite nanoparticles or a dispersion thereof can be obtained.
更に、本発明における金属／粘土鉱物複合ナノ粒子は、複数の金属ナノ結晶が粒子内でランダムに分布してなくて高次構造を形成しているものが必須である。より好ましくは、中心部（コア）と外周部（シェル）が異なる金属ナノ粒子からなるコアシェル構造を形成しているものであり、更に好ましくは、シェル部に貴金属ナノ結晶などの高機能性ナノ結晶を含むコアシェル構造を有するものである。また、最外表面が平滑でなく、微細な凹凸を有するものは特に好ましい。コアとシェルを形成する金属種は、下記に示す製造方法により、異なる金属種の中から実用に適したものを選択できる。また、コア及びシェル部はそれぞれが単独の金属ナノ結晶からなるものであっても、どちらか一つまたは両方ともが複数の金属ナノ結晶からなるものであってもよい。更に、コア及びシェルの質量比率は、目的に応じて任意に制御することが可能である。 Furthermore, it is essential that the metal / clay mineral composite nanoparticles in the present invention are those in which a plurality of metal nanocrystals are not randomly distributed within the particles but have a higher order structure. More preferably, the core part (core) and the outer peripheral part (shell) form a core-shell structure composed of different metal nanoparticles, and more preferably a highly functional nanocrystal such as a noble metal nanocrystal in the shell part. It has a core shell structure containing. Moreover, the outermost surface is not particularly smooth and has fine irregularities. As the metal species forming the core and the shell, those suitable for practical use can be selected from different metal species by the production method shown below. In addition, each of the core and the shell portion may be composed of a single metal nanocrystal, or one or both may be composed of a plurality of metal nanocrystals. Furthermore, the mass ratio of the core and the shell can be arbitrarily controlled according to the purpose.
本発明におけるコアシェル構造を有する金属／粘土鉱物ナノ粒子およびその分散液を製造する方法としては、粘土鉱物存在下で複数の金属化合物の還元力の差を用いる方法（還元力が高い方がコアとなる）、及び、粘土鉱物存在下で金属化合物を添加する順序を用いる方法（先に添加して還元させる方がコアとなる）が有効であり、前者の方法は極めて簡便にコアシェル構造を有する金属／粘土鉱物複合ナノ粒子が得られる点で特に好ましい。また、後者の方法は、金属種の還元力に関わらず、任意の金属ナノ結晶をコアまたはシェルにすることが出来る点で特に好ましい。 As a method for producing metal / clay mineral nanoparticles having a core-shell structure and a dispersion thereof in the present invention, a method using a difference in reducing power of a plurality of metal compounds in the presence of clay mineral (the higher reducing power is the And the method using the order of adding the metal compound in the presence of clay mineral (the one that is added and reduced first becomes the core) is effective, and the former method is a metal having a core-shell structure very easily. / It is particularly preferred in that clay mineral composite nanoparticles can be obtained. The latter method is particularly preferable in that any metal nanocrystal can be used as the core or shell regardless of the reducing power of the metal species.
本発明においてコアシェル構造を有する複数の金属ナノ結晶及び安定したその水分散液を得るには、層状剥離した粘土鉱物を併せて用いることが必須である。本発明における粘土鉱物としては、層状に剥離することができるものであることが必須であり、好ましくは水又は水溶液中で膨潤して層状剥離するものであること、より好ましくは金属化合物を含む水溶液中でマクロに凝集せず、層状剥離した状態で分散できるものである。層状剥離の状態としては１０層以下に層状剥離していることが好ましく、より好ましくは３層以下、特に好ましくは１層又は２層の厚みに層状剥離して分散しているものである。更に、層状剥離した粘土鉱物としては、水媒体中で金属化合物イオンと静電相互作用するもの、及び／または、金属化合物を還元又は還元を促進する性質を有するものが特に好ましい。かかる粘土鉱物としては、例えば、水膨潤性スメクタイト類や水膨潤性雲母などの水中で膨潤し、層状剥離した状態で微分散することが可能な表面負電荷を有する無機層状粘土鉱物が用いられる。具体的には、水膨潤性ヘクトライト、水膨潤性モンモリロナイト、水膨潤性サポナイト及び水膨潤性合成雲母などが挙げられる。また、粘度鉱物の層状剥離を容易にするため、有機分散剤を無機層状鉱物に含ませたものを用いることもできる。例えば、有機分散剤としては、リン酸塩やピロリン酸塩などがあげられる。 In order to obtain a plurality of metal nanocrystals having a core-shell structure and a stable aqueous dispersion thereof in the present invention, it is essential to use a layered exfoliated clay mineral together. As the clay mineral in the present invention, it is essential that the layer can be exfoliated in a layered manner, preferably one that swells in water or an aqueous solution and exfoliates in a layered state, more preferably an aqueous solution containing a metal compound. It does not agglomerate macroscopically and can be dispersed in a layered state. The state of layer peeling is preferably 10 layers or less, more preferably 3 layers or less, and particularly preferably 1 layer or 2 layers. Furthermore, the layered exfoliated clay mineral is particularly preferably one that electrostatically interacts with metal compound ions in an aqueous medium and / or one that has the property of reducing or accelerating metal compounds. As such a clay mineral, for example, an inorganic layered clay mineral having a negative surface charge that can swell in water such as water-swellable smectites and water-swellable mica and finely disperse in a layered state is used. Specific examples include water-swellable hectorite, water-swellable montmorillonite, water-swellable saponite, and water-swellable synthetic mica. Moreover, in order to facilitate the laminar peeling of the viscous mineral, an organic dispersant containing an inorganic layered mineral can also be used. For example, examples of the organic dispersant include phosphate and pyrophosphate.
本発明における金属／粘土鉱物複合ナノ粒子及びその分散液を得る具体的な手法としては、以下の方法が好ましく用いられる。即ち、層状剥離した粘土鉱物を含む水分散液に、複数の金属化合物を同時に添加した後、還元剤を添加し、それらを保持することによる方法、または、層状剥離した粘土鉱物を含む水分散液に、少なくとも一種の金属化合物を添加した後、還元剤を添加し、その後、時間をおいて他の金属化合物を添加し、更にそれらを保持する方法である。ここで、前法において、複数の金属化合物を同時に添加するということは、正確に同時でなくても、殆ど時間をおかず連続して添加することでもよく、予め複数の金属化合物を混合した溶液を添加してもよい。また、後法において、時間をおいて他の金属化合物を添加する場合の時間としては、先に添加した金属化合物が還元された後に加えるのが好ましい。更に、金属／粘土鉱物複合ナノ粒子の分散液の製造法としては、上記のようにワンポットで製造するほか、得られた金属／粘土鉱物複合ナノ粒子分散液から金属／粘土鉱物複合ナノ粒子を精製した後、水または粘土鉱物水分散液に再分散させる方法も用いられる。 As a specific method for obtaining the metal / clay mineral composite nanoparticles and the dispersion thereof in the present invention, the following methods are preferably used. That is, a method in which a plurality of metal compounds are simultaneously added to an aqueous dispersion containing layered exfoliated clay mineral and then a reducing agent is added and retained, or an aqueous dispersion containing layered exfoliated clay mineral In addition, after adding at least one kind of metal compound, a reducing agent is added, and then another metal compound is added after a certain period of time, and these are retained. Here, in the previous method, adding a plurality of metal compounds at the same time may not be exactly the same, but may be added continuously with almost no time, and a solution in which a plurality of metal compounds are mixed in advance. It may be added. Further, in the subsequent method, it is preferable to add the other metal compound after the metal compound added earlier has been reduced as the time when the other metal compound is added at a later time. Furthermore, as a method for producing a dispersion of metal / clay mineral composite nanoparticles, one-pot production as described above, and purification of metal / clay mineral composite nanoparticles from the obtained metal / clay mineral composite nanoparticle dispersion Then, a method of redispersing in water or an aqueous dispersion of clay mineral is also used.
また、本発明における金属／粘土鉱物複合ナノ粒子の製造法において、金属化合物を添加した後、超音波をかけることは、全体として均一な金属／粘土鉱物複合ナノ粒子及びその分散液を製造するのに有効である。超音波をかける時間は必ずしも限定されないが、好ましくは１０秒〜１００分の間から選択される。 Further, in the method for producing metal / clay mineral composite nanoparticles in the present invention, applying a ultrasonic wave after adding a metal compound produces a uniform metal / clay mineral composite nanoparticles and a dispersion thereof as a whole. It is effective for. The time for applying the ultrasonic wave is not necessarily limited, but is preferably selected from 10 seconds to 100 minutes.
また、本発明における金属化合物の金属ナノ結晶への還元は室温付近で行うことが最も好ましい。即ち、還元反応は５〜８０℃の範囲で行えるが、明確なコアシェル構造などの内部構造の形成、及び安定した分散液の調製のためには、好ましくは５〜５０℃、より好ましくは、１０〜４０℃、特に好ましくは、１５〜３５℃の範囲で行うことである。 In addition, the reduction of the metal compound to the metal nanocrystal in the present invention is most preferably performed near room temperature. That is, the reduction reaction can be carried out in the range of 5 to 80 ° C., but preferably 5 to 50 ° C., more preferably 10 for the formation of a clear internal structure such as a core-shell structure and the preparation of a stable dispersion. It is -40 degreeC, Most preferably, it is carrying out in 15-35 degreeC.
また、本発明においては層状剥離した粘土鉱物と共に還元剤を併用することが必須である。本発明における還元剤としては、金属化合物を還元し、複数の金属ナノ結晶を合成できるものであれば良く、必ずしも限定されるものではないが、より好ましくは、層状剥離した粘土鉱物の存在下で、金属化合物を還元し、微細な金属ナノナノ結晶を調製できるものが用いられる。用いられる還元剤としては、例えば、水素、水素化ホウ素ナトリウム、水素化ホウ素アンモニウムなどのホウ素化合物、メタノール、エタノール、プロパノール、イソプロピルアルコール、エチレングリコール、プロピレングリコールなどのアルコール類、ホルムアルデヒド、アセトアルデヒド、プロピオンアルデヒドなどのアルデヒド類、アスコルビン酸、クエン酸、クエン酸ナトリウムなどの酸類、プロピルアミン、ブチルアミン、ジエチルアミン、ジプロピルアミン、ジメチルエチルアミン、トリエチルアミン、エチレンジアミン、トリエチレンテトラミン、メチルアミノエタノール、ジメチルアミノエタノール、トリエタノールアミンなどのアミン類、ヒドラジン、炭酸ヒドラジンなどのヒドラジン類、水酸化ナトリウム、水酸化カリウムなどのアルカリ類などが挙げられる。これらのなかでも、水素化ホウ素ナトリウムまたはアスコルビン酸はより好ましく、特に貴金属ナノ結晶の調製やコアシェル構造形成のためには、アスコルビン酸が特に好ましい。また、還元剤の使用量は、金属化合物中の金属イオンを還元するのに必要な量以上であれば特に限定されるものではなく、上限は特に規定するものではないが、金属イオンの１０モル倍以下であることが好ましく、２モル倍以下であることがより好ましい。また、還元剤の添加方法も限定されるものではなく、例えば、還元剤をそのまま、又は水溶液やその他の溶媒に溶解、分散させて混合させることができる。 In the present invention, it is essential to use a reducing agent in combination with the layered exfoliated clay mineral. The reducing agent in the present invention is not limited as long as it can reduce a metal compound and synthesize a plurality of metal nanocrystals, but more preferably, in the presence of a layered exfoliated clay mineral. A metal compound that can be reduced to prepare fine metal nano-nanocrystals is used. Examples of the reducing agent used include boron compounds such as hydrogen, sodium borohydride, and ammonium borohydride, alcohols such as methanol, ethanol, propanol, isopropyl alcohol, ethylene glycol, and propylene glycol, formaldehyde, acetaldehyde, and propionaldehyde. Aldehydes such as, acids such as ascorbic acid, citric acid, sodium citrate, propylamine, butylamine, diethylamine, dipropylamine, dimethylethylamine, triethylamine, ethylenediamine, triethylenetetramine, methylaminoethanol, dimethylaminoethanol, triethanol Amines such as amines, hydrazines such as hydrazine and hydrazine carbonate, sodium hydroxide, hydroxide Umm, and the like alkali such as. Among these, sodium borohydride or ascorbic acid is more preferable, and ascorbic acid is particularly preferable for the preparation of noble metal nanocrystals and the formation of a core-shell structure. Further, the amount of the reducing agent used is not particularly limited as long as it is more than the amount necessary for reducing the metal ion in the metal compound, and the upper limit is not particularly specified, but 10 mol of the metal ion. It is preferably 2 times or less, more preferably 2 mole times or less. Moreover, the addition method of a reducing agent is not limited, either, For example, a reducing agent can be mixed as it is, or it melt | dissolves and disperses in aqueous solution or another solvent.
また本発明においては、金属化合物の還元を制御したり、還元を促進する物質として、水溶性有機高分子（例えば、エチレングリコール、ジエチレングリコール、トリエチレングリコールなどのポリオール類、ポリビニルピロリドン、ポリアリルアミン、ポリエチレンイミンなどの水溶性高分子の一種以上又は共重合体）を上記還元剤と共に用いることも有効に用いられる。 In the present invention, water-soluble organic polymers (for example, polyols such as ethylene glycol, diethylene glycol, and triethylene glycol, polyvinyl pyrrolidone, polyallylamine, polyethylene) are used as substances that control or accelerate the reduction of metal compounds. It is also effective to use one or more water-soluble polymers such as imine or a copolymer) together with the reducing agent.
本発明における金属化合物としては、水溶性金属化合物であって、還元反応によって金属ナノ結晶が得られるものが用いられる。例えば、金属カチオンと対アニオンとの塩類のもの、あるいは金属が対アニオンの中に含まれるものなどが用いられる。例えば、銀の場合、硝酸銀、酸化銀、酢酸銀、フッ化銀、銀アセチルアセトナート、安息香酸銀、クエン酸銀、銀ヘキサフルオロフォスジェート、乳酸銀、亜硝酸銀、ペンタフルオロプロピオン酸銀など、白金やパラジウムの場合は塩化白金カリウム（Ｋ２ＰｔＣｌ４）や塩化パラジウムカリウム（Ｋ２ＰｄＣｌ４）など、金の場合は四塩化金ナトリウム水和物（Ｎａ（ＡｕＣｌ４）・２Ｈ２Ｏ）、ニッケルや鉄の場合は塩化ニッケル（ＮｉＣｌ２）や塩化鉄（ＦｅＣｌ３）など、コバルトや銅の場合は硫酸コバルト水和物（ＣｏＳＯ４・７Ｈ２Ｏ）や硫酸銅水和物（ＣｕＳＯ４・５Ｈ２Ｏ）などがあげられる。 As the metal compound in the present invention, a water-soluble metal compound which can obtain metal nanocrystals by a reduction reaction is used. For example, a salt of a metal cation and a counter anion, or one in which a metal is contained in the counter anion is used. For example, in the case of silver, silver nitrate, silver oxide, silver acetate, silver fluoride, silver acetylacetonate, silver benzoate, silver citrate, silver hexafluorophosphate, silver lactate, silver nitrite, silver pentafluoropropionate, etc. In the case of platinum or palladium, potassium potassium chloride (K2PtCl4) or potassium potassium chloride (K2PdCl4), in the case of gold, sodium tetrachloride hydrate (Na (AuCl4) · 2H2O), in the case of nickel or iron, nickel chloride In the case of cobalt and copper, such as (NiCl2) and iron chloride (FeCl3), cobalt sulfate hydrate (CoSO4 · 7H2O), copper sulfate hydrate (CuSO4 · 5H2O) and the like can be mentioned.
本発明における金属／粘土鉱物複合ナノ粒子分散液の分散媒体としては、好ましくは水が用いられるが、他の有機溶媒や水溶性物質を含む水溶液も用いられる。また、一端、水又は水溶液を用いて金属ナノ粒子分散液を調製した後、媒体を有機溶媒に変更することも可能である。 As the dispersion medium of the metal / clay mineral composite nanoparticle dispersion liquid in the present invention, water is preferably used, but an aqueous solution containing another organic solvent or a water-soluble substance is also used. It is also possible to change the medium to an organic solvent after preparing a metal nanoparticle dispersion using one end, water or an aqueous solution.
本発明で得られる金属ナノ粒子分散液は、金属／粘土鉱物複合ナノ粒子が小さく且つ均一であることに加えて、共存する層状剥離した粘土鉱物の働きで、優れた分散安定性を有する。また、得られた金属／粘土鉱物複合ナノ粒子分散液は、含まれる粘土鉱物の濃度により、低粘度のゾルから、高粘度、そしてゲル状態まで、粘度を広範囲に制御することができる。また、撹拌状態ではゾルで、静置状態ではゲルとなるものも調製可能である。いずれにおいても金属／粘土鉱物複合ナノ粒子分散液は優れた分散安定性を示す。例えば、本発明における金属／粘土鉱物複合ナノ粒子分散液は、数日以上、好ましくは数ヶ月以上にわたって安定であり不均一な凝集や沈殿を生じることがない。 The metal nanoparticle dispersion obtained in the present invention has excellent dispersion stability due to the coexistence of the layered exfoliated clay mineral in addition to the small and uniform metal / clay mineral composite nanoparticles. Further, the obtained metal / clay mineral composite nanoparticle dispersion can control the viscosity in a wide range from a low-viscosity sol to a high-viscosity and gel state depending on the concentration of the clay mineral contained. Moreover, what becomes a sol in a stirring state and becomes a gel in a stationary state can also be prepared. In any case, the metal / clay mineral composite nanoparticle dispersion exhibits excellent dispersion stability. For example, the metal / clay mineral composite nanoparticle dispersion in the present invention is stable for several days or more, preferably for several months or more, and does not cause uneven aggregation or precipitation.
本発明における金属／粘土鉱物複合ナノ粒子は、得られた金属／粘土鉱物複合ナノ粒子分散液をスプレードライなどの方法で直接粒子状態とした後、乾燥及び／又は熱処理する方法や、金属／粘土鉱物複合ナノ粒子分散液を高分子、紙、ガラス、セラミック、金属などの基材上に、そのまま、もしくは他の有機及び／又は無機素材と混合した後、塗布し、引き続き、乾燥及び／又は熱処理する方法により得られる。また、金属ナノ粒子を基材の上でミクロなパターン形成を行わせることも有効に用いられる。 In the present invention, the metal / clay mineral composite nanoparticles are obtained by directly converting the obtained metal / clay mineral composite nanoparticle dispersion into a particle state by a method such as spray drying, followed by drying and / or heat treatment, or metal / clay. The mineral composite nanoparticle dispersion is applied to a substrate such as polymer, paper, glass, ceramic, metal, etc. as it is or after being mixed with other organic and / or inorganic materials, and then applied, followed by drying and / or heat treatment. It is obtained by the method to do. It is also effective to cause the metal nanoparticles to form a micro pattern on the substrate.
次いで本発明を実施例により、より具体的に説明するが、もとより本発明は、以下に示す実施例にのみ限定されるものではない。
（実施例１、比較例１）
水膨潤性層状粘土鉱物であるスメクタイト類の一種である合成ヘクトライト（ラポナイトＸＬＧ：Rockwood社）を２質量％含む均一透明な（水中で層状剥離した）粘土鉱物水分散液１０ｍｌに、２５℃で、２０ｍMのK2PtCl4水溶液１０ｍｌと２０ｍMのK2PdCl4水溶液１０ｍｌを添加し、次いで０．４Mのアスコルビン酸水溶液４ｍｌを添加した後、１０分間（室温で）超音波にかけた。得られた液を２４時間、２５℃で保持した。その結果、沈殿のない、均一な黒色水分散液が得られた。これを遠心分離（一万回転、１０分間）することにより固体を沈殿回収した後、再度水に分散した。この遠心分離−沈殿−再分散を３回繰り返して、精製した固体及びその水分散液を得た。水分散液を透過型電子顕微鏡（ＴＥＭ）用のカーボン膜の上に垂らし、溶媒（水）を乾燥により除いてから、ＴＥＭ（日本電子製JEM−２２００TFE：２００ｋV）測定を行った。得られた結果を図１に示す。平均粒径７０ｎｍの粒子が観測され、その外周部は微細な凹凸構造を有することが確認された。単一ナノ粒子の元素分析結果を図２に示す。また、Ｍｇ，ＰｔおよびＰｄのエネルギー分散Ｘ線マッピング測定（走査TEM検出器付きJEM-2200TFE（200kV）使用）結果を各々、図３（ａ）、（ｂ）及び（ｃ）に、また、図３（ｂ）と（ｃ）を併せた結果を図３（ｄ）に示す。更に、Ｘ線光電子スペクトル測定（日本電子製ＥＳＣＡＬａｂ ＭＫＩＩ（ＭｇＫ）使用）結果を図４に、広角X線回析測定（理学電機製Ｒｉｇａｋｕ ＳｍａｒｔＬａｂ（ＣｕＫ）使用）結果を図５に示す。以上の結果から、水分散液には、平均粒径が６５ｎｍのＰｄナノ結晶−Ｐｔナノ結晶−粘土鉱物からなる金属／粘土鉱物複合ナノ粒子が形成していること、且つ、Ｐｄナノ結晶をコア、Ｐｔナノ結晶をシェルとするコアシェル構造を有していることが明らかとなった。得られたＰｔ−Ｐｄ−粘土鉱物複合ナノ粒子の窒素吸着法によるＢＥＴ表面積測定（BEL Japan Inc製BELSORP-mini II使用）結果は２９０．７ｍ２／ｇであり、非常に高い値を示した。
得られたＰｄ−Ｐｔ−粘土鉱物複合ナノ粒子の触媒活性を調べるため、以下の実験を行った。６０ｍＭのＮａＢＨ４水溶液０．５ｍｌを、０．１２ｍＭの４−ニトロフェノール水溶液２．５ｍｌに加えた。３ｍｇのＰｄ−Ｐｔ−粘土鉱物複合ナノ粒子を添加し、撹拌して保持した（２５℃）。金属／粘土鉱物複合ナノ粒子を添加した後の、６０秒毎の紫外線吸収スペクトル（２５０−５５０ｎｍ）測定した結果、４−ニトロフェノールが４−アミノフェノールに還元されるのが観測され、表１に示す速度定数と活性パラメーターが得られた。市販の白金触媒（PtBlack）を用いた場合（比較例１）に比べて、高い触媒活性を示すことが確認された。
EXAMPLES Next, although an Example demonstrates this invention more concretely, this invention is not limited only to the Example shown below from the first.
(Example 1, Comparative Example 1)
To 10 ml of a uniform and transparent clay mineral aqueous dispersion containing 2% by mass of synthetic hectorite (Laponite XLG: Rockwood), a kind of smectites that are water-swellable layered clay minerals, at 25 ° C. Then, 10 ml of 20 mM aqueous K2PtCl4 solution and 10 ml of 20 mM aqueous K2PdCl4 solution were added, and then 4 ml of 0.4 M aqueous ascorbic acid solution was added, followed by ultrasonication for 10 minutes (at room temperature). The resulting liquid was kept at 25 ° C. for 24 hours. As a result, a uniform black water dispersion without precipitation was obtained. This was centrifuged (10,000 rotations, 10 minutes) to precipitate and recover a solid, and then dispersed again in water. This centrifugation-precipitation-redispersion was repeated three times to obtain a purified solid and its aqueous dispersion. The aqueous dispersion was dropped on a carbon film for a transmission electron microscope (TEM), the solvent (water) was removed by drying, and TEM (JEM-2200 TFE: 200 kV) was measured. The obtained results are shown in FIG. Particles having an average particle diameter of 70 nm were observed, and the outer periphery thereof was confirmed to have a fine uneven structure. The result of elemental analysis of a single nanoparticle is shown in FIG. In addition, the results of energy dispersive X-ray mapping measurement (using JEM-2200TFE (200 kV) with scanning TEM detector) of Mg, Pt and Pd are shown in FIGS. 3 (a), (b) and (c), respectively. The result of combining 3 (b) and (c) is shown in FIG. 3 (d). Further, FIG. 4 shows the results of X-ray photoelectron spectrum measurement (using ESCALab MKII (MgK) manufactured by JEOL), and FIG. 5 shows the results of wide-angle X-ray diffraction measurement (using Rigaku SmartLab (CuK) manufactured by Rigaku Corporation). From the above results, the aqueous dispersion is formed with metal / clay mineral composite nanoparticles composed of Pd nanocrystals-Pt nanocrystals-clay minerals with an average particle size of 65 nm, and the Pd nanocrystals are cores. It was revealed that it has a core-shell structure with Pt nanocrystals as the shell. The obtained Pt-Pd-clay mineral composite nanoparticles were measured for BET surface area by nitrogen adsorption method (using BELSORP-mini II manufactured by BEL Japan Inc). The result was 290.7 m2 / g, which was a very high value.
In order to investigate the catalytic activity of the obtained Pd—Pt—clay mineral composite nanoparticles, the following experiment was conducted. 0.5 ml of 60 mM NaBH4 aqueous solution was added to 2.5 ml of 0.12 mM 4-nitrophenol aqueous solution. 3 mg of Pd—Pt—clay mineral composite nanoparticles were added and held with stirring (25 ° C.). As a result of measuring an ultraviolet absorption spectrum (250-550 nm) every 60 seconds after adding metal / clay mineral composite nanoparticles, it was observed that 4-nitrophenol was reduced to 4-aminophenol. The indicated rate constants and activity parameters were obtained. Compared with the case where a commercially available platinum catalyst (PtBlack) was used (Comparative Example 1), it was confirmed that high catalytic activity was exhibited.
（実施例２、３）
実施例２では、K2PtCl4水溶液の代わりに２０ｍMのNa(AuCl4)2H2O水溶液１０ｍｌを用いること、実施例３では、K2PdCl4水溶液の代わりに２０ｍMのNa(AuCl4)2H2O水溶液１０ｍｌを用いること以外は、実施例１と同様にして実験を行った。実施例１と同様にして測定したTEM測定結果及びエネルギー分散Ｘ線マッピング測定結果を図６（ａ）及び（ｂ）（実施例２）、図７（ａ）及び（ｂ）（実施例３）に、また、Ｘ線光電子スペクトル測定結果を図８（実施例２）及び図９（実施例３）に示す。更に実施例２の広角Ｘ線回折測定結果を図１０に示す。以上のことから、実施例２では、Ａｕナノ結晶−Ｐｄナノ結晶−粘土鉱物複合ナノ粒子（平均粒径６０ｎｍ、Ａｕナノ結晶がコア、Ｐｄナノ結晶がシェル）及びその分散液が得られたこと、実施例３では、Ａｕナノ結晶−Ｐｔナノ結晶−粘土鉱物複合ナノ粒子（平均粒径５５ｎｍ、Ａｕナノ結晶がコア、Ｐｄナノ結晶がシェル）及びその分散液が得られたことが明らかとなった。実施例２のＡｕナノ結晶−Ｐｄナノ結晶−粘土鉱物複合ナノ粒子のＢＥＴ表面積は３４３．５ｍ２／ｇであった。
(Examples 2 and 3)
In Example 2, 10 ml of 20 mM Na (AuCl4) 2H2O aqueous solution was used instead of K2PtCl4 aqueous solution, and in Example 3, 10 ml of 20 mM Na (AuCl4) 2H2O aqueous solution was used instead of K2PdCl4 aqueous solution. The experiment was conducted in the same manner as in 1. TEM measurement results and energy dispersive X-ray mapping measurement results measured in the same manner as in Example 1 are shown in FIGS. 6 (a) and 6 (b) (Example 2), and FIGS. 7 (a) and 7 (b) (Example 3). In addition, the X-ray photoelectron spectrum measurement results are shown in FIG. 8 (Example 2) and FIG. 9 (Example 3). Furthermore, the wide-angle X-ray diffraction measurement result of Example 2 is shown in FIG. From the above, in Example 2, Au nanocrystals-Pd nanocrystals-clay mineral composite nanoparticles (average particle size of 60 nm, Au nanocrystals as cores, Pd nanocrystals as shells) and dispersions thereof were obtained. In Example 3, it was clarified that Au nanocrystals-Pt nanocrystals-clay mineral composite nanoparticles (average particle size 55 nm, Au nanocrystals were cores, Pd nanocrystals were shells) and dispersions thereof were obtained. It was. The BET surface area of the Au nanocrystal-Pd nanocrystal-clay mineral composite nanoparticle of Example 2 was 343.5 m <2> / g.
得られた複合ナノ粒子を用いて４−ニトロフェノールの還元反応に対する触媒活性を実施例１と同様に測定した結果を表１に示す。いずれも比較触媒（Pt-Black）より高い活性を示し、特にＡｕナノ結晶−Ｐｄナノ結晶−粘土鉱物複合ナノ粒子は優れた触媒活性を示した。 Table 1 shows the results of measuring the catalytic activity for the reduction reaction of 4-nitrophenol in the same manner as in Example 1 using the obtained composite nanoparticles. All showed higher activity than the comparative catalyst (Pt-Black), and in particular, Au nanocrystal-Pd nanocrystal-clay mineral composite nanoparticles showed excellent catalytic activity.
（実施例４）
粘土鉱物水分散液に加える金属化合物水溶液および還元剤の添加順序が異なる、即ち、最初にK2PtCl4水溶液を加え、次いで、アスコルビン酸水溶液を加え、３時間後に、K2PdCl4水溶液を加えること以外は実施例１と同様にして実験を行った。実施例１と同様にして測定したTEM測定結果及びエネルギー分散Ｘ線マッピング測定結果を図１１及び図１２に示す。これらから、平均粒径が５４ｎｍ、Ｐｔナノ結晶がコア、Ｐｄナノ結晶がシェルのＰｔナノ結晶−Ｐｄナノ結晶−粘土鉱物複合ナノ粒子が得られたことが明らかとなった。
Example 4
Example 1 except that the addition order of the metal compound aqueous solution and the reducing agent added to the clay mineral aqueous dispersion is different, that is, the K2PtCl4 aqueous solution is added first, then the ascorbic acid aqueous solution is added, and the K2PdCl4 aqueous solution is added after 3 hours. The experiment was conducted in the same manner as above. TEM measurement results and energy dispersive X-ray mapping measurement results measured in the same manner as in Example 1 are shown in FIGS. From these results, it was clarified that Pt nanocrystal-Pd nanocrystal-clay mineral composite nanoparticles having an average particle size of 54 nm, Pt nanocrystals as a core, and Pd nanocrystals as a shell were obtained.
（実施例５、６）
アスコルビン酸水溶液の代わりに０．１MのNaBH4水溶液１０ｇを用いること、及び第二の金属化合物水溶液をNaBH4水溶液添加してから２４時間後に行うこと、また、第二の金属化合物水溶液として、K2PdCl4水溶液の代わりに２０ｍMのCoSO47H2Oの水溶液１０ｇを用いること（実施例５）または２０ｍMのNiCl2水溶液１０ｇを用いること（実施例６）を除くと、実施例４と同様にして実験を行った。その結果、実施例５では平均２１ｎｍのＰｔナノ結晶−Ｃｏナノ結晶−粘土鉱物複合ナノ粒子が、また、実施例６では平均１０ｎｍのＰｔナノ結晶−Ｎｉナノ結晶−粘土鉱物複合ナノ粒子が得られることが明らかとなった。図１３に実施例５で得られたＰｔナノ結晶−Ｃｏナノ結晶−粘土鉱物複合ナノ粒子のＴＥＭ写真を示す。これらの複合ナノ粒子０．０５ｇを用いて実施例１と同様にして４−ニトロフェノールの還元反応に対する触媒活性を調べた結果を表１に示す。いずれも極めて高い触媒活性を示した。
(Examples 5 and 6)
Use 10 g of 0.1M NaBH4 aqueous solution instead of ascorbic acid aqueous solution, and perform 24 hours after adding the second metal compound aqueous solution to the NaBH4 aqueous solution. Also, as the second metal compound aqueous solution, K2PdCl4 aqueous solution Instead of using 10 g of a 20 mM aqueous solution of CoSO47H2O (Example 5) or using 10 g of a 20 mM aqueous NiCl2 solution (Example 6), the experiment was conducted in the same manner as in Example 4. As a result, Pt nanocrystal-Co nanocrystal-clay mineral composite nanoparticles having an average of 21 nm are obtained in Example 5, and Pt nanocrystal-Ni nanocrystal-clay mineral composite nanoparticles having an average of 10 nm are obtained in Example 6. It became clear. FIG. 13 shows a TEM photograph of the Pt nanocrystal-Co nanocrystal-clay mineral composite nanoparticles obtained in Example 5. Table 1 shows the results of examining the catalytic activity for the reduction reaction of 4-nitrophenol in the same manner as in Example 1 using 0.05 g of these composite nanoparticles. All showed extremely high catalytic activity.
（比較例２）
粘土鉱物を用いない、即ち、粘土鉱物水分散液のかわりに水を用いること以外は実施例１と同様に実験を行った。その結果、均一な黒色水分散液は得られず、黒色の凝集沈殿物が得られた。
(Comparative Example 2)
The experiment was conducted in the same manner as in Example 1 except that no clay mineral was used, that is, water was used instead of the clay mineral aqueous dispersion. As a result, a uniform black water dispersion was not obtained, and a black aggregated precipitate was obtained.
表１
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| WO2020054597A1 (en) * | 2018-09-11 | 2020-03-19 | 公立大学法人首都大学東京 | Gold-supporting catalyst |
| CN114951687A (en) * | 2022-06-30 | 2022-08-30 | 淮安中顺环保科技有限公司 | Room temperature macro preparation method of attapulgite-nano copper powder compound |
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| WO2020054597A1 (en) * | 2018-09-11 | 2020-03-19 | 公立大学法人首都大学東京 | Gold-supporting catalyst |
| US11931726B2 (en) | 2018-09-11 | 2024-03-19 | Tokyo Metropolitan University | Gold-supporting catalyst |
| CN114951687A (en) * | 2022-06-30 | 2022-08-30 | 淮安中顺环保科技有限公司 | Room temperature macro preparation method of attapulgite-nano copper powder compound |
| CN114951687B (en) * | 2022-06-30 | 2024-02-13 | 淮安中顺环保科技有限公司 | Room temperature macro preparation method of attapulgite-nanometer copper powder compound |
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