JP3567004B2 - Photocatalyst and method for producing the same - Google Patents
Photocatalyst and method for producing the same Download PDFInfo
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- JP3567004B2 JP3567004B2 JP33945194A JP33945194A JP3567004B2 JP 3567004 B2 JP3567004 B2 JP 3567004B2 JP 33945194 A JP33945194 A JP 33945194A JP 33945194 A JP33945194 A JP 33945194A JP 3567004 B2 JP3567004 B2 JP 3567004B2
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- Prior art keywords
- titanium oxide
- compound
- photocatalyst
- potassium
- present
- Prior art date
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- 239000011941 photocatalyst Substances 0.000 title claims description 62
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 77
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 75
- -1 aluminum compound Chemical class 0.000 claims description 64
- 150000003112 potassium compounds Chemical class 0.000 claims description 46
- 239000002245 particle Substances 0.000 claims description 44
- 229910052782 aluminium Inorganic materials 0.000 claims description 34
- 229910052698 phosphorus Inorganic materials 0.000 claims description 34
- 239000011574 phosphorus Substances 0.000 claims description 34
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 13
- 238000001354 calcination Methods 0.000 claims description 8
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 7
- 239000011591 potassium Substances 0.000 claims description 7
- 229910052700 potassium Inorganic materials 0.000 claims description 7
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 3
- 239000000758 substrate Substances 0.000 claims 1
- 230000001699 photocatalysis Effects 0.000 description 24
- 239000000126 substance Substances 0.000 description 16
- 238000000034 method Methods 0.000 description 15
- 230000000052 comparative effect Effects 0.000 description 14
- 238000006243 chemical reaction Methods 0.000 description 13
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 12
- 239000000725 suspension Substances 0.000 description 11
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 8
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- 150000003839 salts Chemical class 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 5
- 238000000354 decomposition reaction Methods 0.000 description 5
- 238000010304 firing Methods 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 150000002896 organic halogen compounds Chemical class 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- 150000004820 halides Chemical class 0.000 description 2
- 150000004679 hydroxides Chemical class 0.000 description 2
- 230000003100 immobilizing effect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 2
- 229910052753 mercury Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 150000002823 nitrates Chemical class 0.000 description 2
- 229910017464 nitrogen compound Inorganic materials 0.000 description 2
- 150000002830 nitrogen compounds Chemical class 0.000 description 2
- 150000002903 organophosphorus compounds Chemical class 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
- 238000013032 photocatalytic reaction Methods 0.000 description 2
- 230000001443 photoexcitation Effects 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- LLZRNZOLAXHGLL-UHFFFAOYSA-J titanic acid Chemical compound O[Ti](O)(O)O LLZRNZOLAXHGLL-UHFFFAOYSA-J 0.000 description 2
- 150000003609 titanium compounds Chemical class 0.000 description 2
- 229910000349 titanium oxysulfate Inorganic materials 0.000 description 2
- 229910000348 titanium sulfate Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- HZAXFHJVJLSVMW-UHFFFAOYSA-N 2-Aminoethan-1-ol Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 description 1
- 241000186361 Actinobacteria <class> Species 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical class [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 241000894006 Bacteria Species 0.000 description 1
- 208000035985 Body Odor Diseases 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 241000195493 Cryptophyta Species 0.000 description 1
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical class S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 1
- 241000233866 Fungi Species 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- CYTYCFOTNPOANT-UHFFFAOYSA-N Perchloroethylene Chemical group ClC(Cl)=C(Cl)Cl CYTYCFOTNPOANT-UHFFFAOYSA-N 0.000 description 1
- ABLZXFCXXLZCGV-UHFFFAOYSA-N Phosphorous acid Chemical compound OP(O)=O ABLZXFCXXLZCGV-UHFFFAOYSA-N 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 206010040904 Skin odour abnormal Diseases 0.000 description 1
- XSTXAVWGXDQKEL-UHFFFAOYSA-N Trichloroethylene Chemical group ClC=C(Cl)Cl XSTXAVWGXDQKEL-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 239000000809 air pollutant Substances 0.000 description 1
- 231100001243 air pollutant Toxicity 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
- 150000001412 amines Chemical class 0.000 description 1
- 150000001413 amino acids Chemical class 0.000 description 1
- 239000000908 ammonium hydroxide Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000007611 bar coating method Methods 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 150000001845 chromium compounds Chemical class 0.000 description 1
- 235000019504 cigarettes Nutrition 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000010411 cooking Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 239000002781 deodorant agent Substances 0.000 description 1
- 238000003618 dip coating Methods 0.000 description 1
- XQRLCLUYWUNEEH-UHFFFAOYSA-N diphosphonic acid Chemical compound OP(=O)OP(O)=O XQRLCLUYWUNEEH-UHFFFAOYSA-N 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000000417 fungicide Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 239000004009 herbicide Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 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
- TVZISJTYELEYPI-UHFFFAOYSA-N hypodiphosphoric acid Chemical compound OP(O)(=O)P(O)(O)=O TVZISJTYELEYPI-UHFFFAOYSA-N 0.000 description 1
- 150000002484 inorganic compounds Chemical class 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000002917 insecticide Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 239000005645 nematicide Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 150000002825 nitriles Chemical class 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 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
- 229910052763 palladium Inorganic materials 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 229940085991 phosphate ion Drugs 0.000 description 1
- ACVYVLVWPXVTIT-UHFFFAOYSA-N phosphinic acid Chemical compound O[PH2]=O ACVYVLVWPXVTIT-UHFFFAOYSA-N 0.000 description 1
- 229910001392 phosphorus oxide Inorganic materials 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 150000003071 polychlorinated biphenyls Chemical group 0.000 description 1
- 229910001414 potassium ion Inorganic materials 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 238000007761 roller coating Methods 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000001954 sterilising effect Effects 0.000 description 1
- 238000004659 sterilization and disinfection Methods 0.000 description 1
- 150000003464 sulfur compounds Chemical class 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 229950011008 tetrachloroethylene Drugs 0.000 description 1
- VSAISIQCTGDGPU-UHFFFAOYSA-N tetraphosphorus hexaoxide Chemical compound O1P(O2)OP3OP1OP2O3 VSAISIQCTGDGPU-UHFFFAOYSA-N 0.000 description 1
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 description 1
- UBOXGVDOUJQMTN-UHFFFAOYSA-N trichloroethylene Natural products ClCC(Cl)Cl UBOXGVDOUJQMTN-UHFFFAOYSA-N 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
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- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Description
【０００１】
【産業上の利用分野】
本発明は優れた光触媒機能を有する光触媒およびその製造方法に関する。
【０００２】
【従来の技術】
光触媒に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光励起により伝導帯に電子を、価電子帯に正孔を生じる。この光励起により生じた電子の持つ強い還元力や正孔の持つ強い酸化力は、有害物質の分解や浄化、水の分解、殺菌、有機物合成などの反応に利用されている。たとえば、特公平２−９８５０号公報には、光触媒を用いて廃棄物中の有害物質を分解し、浄化することが記載されている。また、特公平４−７８３２６号公報には、光触媒を用いてトイレのし尿臭、ペットの臭い、タバコの臭い、調理臭、体臭などを脱臭することが記載されている。さらに、特公平−２９３９３号公報には、光励起により生起した所定電圧を細胞に接触印加して細胞を殺すことが記載されている。
【０００３】
【発明が解決しようとする課題】
光触媒を実際の反応に用いるには、反応中においては光触媒が反応系から飛散しないようにする必要があり、また、反応終了後においては光触媒を反応系から分離する必要があるため、光触媒を支持体上に固定した状態で用いている。光触媒を固定化するためには光触媒を支持体に付着させ、次いで、２００〜１０００℃の温度で焼成する方法が通常採られている。しかしながら、光触媒を高温で焼成すると、焼成前のものに比べ、光触媒機能が著しく低下するという問題がある。
また、光触媒を高温の反応で用いる場面が増えつつあること、さらには、光触媒を再生する際に高温で焼成する方法が考えられることなどにより、高温の条件でも光触媒機能が低下しない光触媒が嘱望されている。
さらに、反応時間を短縮したり、反応に用いる装置を小型化したりするため、一層優れた光触媒機能を有する光触媒が以前から嘱望されている。
【０００４】
【課題を解決するための手段】
本発明者らは、高温度の焼成や反応条件による光触媒機能の劣化が少ない酸化チタン光触媒を得るべく研究した結果、（１）酸化チタンの粒子内部および／またはその表面にカリウム化合物を含有させることにより所望の光触媒が得られること、（２）酸化チタンにアルミニウム化合物および／またはリン化合物とカリウム化合物とを含有させることにより、より好ましい光触媒が得られること、（３）前記（１）、（２）の光触媒を製造するには、酸化チタンと、カリウム化合物と、さらには必要に応じてアルミニウム化合物および／またはリン化合物とを接触させて生成物を得、次いで、該生成物を５００〜９００℃の温度で焼成する方法が簡便で好ましいこと、（４）本発明の光触媒を支持体に固定化するには、酸化チタンとカリウム化合物と、さらには必要に応じてアルミニウム化合物および／またはリン化合物とを接触させて生成物を得、次いで、該生成物を支持体に付着させ、次いで、５００〜９００℃の温度で焼成する方法が簡便で好ましいことなどを見出し、本発明を完成した。
【０００５】
すなわち、本発明は優れた光触媒機能を有する酸化チタン光触媒を提供することにある。
【０００６】
本発明はカリウム化合物を酸化チタン粒子の内部および／またはその表面に含有してなる酸化チタン光触媒である。本発明において酸化チタンとは、アナタース型酸化チタン、ルチル型酸化チタン、無定形酸化チタン、メタチタン酸、オルトチタン酸などの各種の酸化チタンあるいは水酸化チタン、含水酸化チタン、水和酸化チタンを意味する。酸化チタンの平均粒子径は、Ｓｃｈｅｒｒｅｒの式より算出して、好ましくは１〜５００ｎｍ、より好ましくは５〜２５０ｎｍ、もっとも好ましくは５〜１００ｎｍである。また、本発明において、カリウム化合物とは、カリウムの酸化物、水酸化物、硫酸塩、ハロゲン化物、硝酸塩などの化合物、さらにはカリウムイオンを含む。カリウムの含有量は、適宜設定できるが、酸化チタンのＴｉＯ２ 重量基準に対して、カリウム化合物をカリウム（Ｋ）基準に換算して、好ましくは０．０１〜１０重量％、より好ましくは０．０３〜５重量％、もっとも好ましくは０．０５〜３重量％である。カリウム化合物が０．０１重量％より少なかったり、また、１０重量％より多かったりすると光触媒機能が低下する場合があるため、好ましくない。本発明の酸化チタン光触媒は、酸化チタンとカリウム化合物との単なる混合物とは異なり、酸化チタンの粒子表面にカリウム化合物を担持あるいは被覆したり、酸化チタンの粒子内部にカリウム化合物をドープしたりして、カリウム化合物が酸化チタンの粒子内部および／または酸化チタンの粒子表面に存在している状態、特に、酸化チタンの粒子内部に少なくとも存在している状態を保持した粒子である。
【０００７】
さらに、本発明は、アルミニウム化合物および／またはリン化合物とカリウム化合物とを含有してなる酸化チタン光触媒である。本発明において、アルミニウム化合物とは、アルミニウムの酸化物、水酸化物、硫酸塩、ハロゲン化物、硝酸塩などの化合物、さらにはアルミニウムイオンを含む。また、リン化合物とは、リンの酸化物、リン酸またはその塩、縮合リン酸またはその塩、ホスフィン酸またはその塩、ホスホン酸またはその塩、ジホスホン酸またはその塩、次リン酸またはその塩などの化合物、さらにはリン酸イオンを含む。アルミニウム化合物および／またはリン化合物の含有量は、適宜設定できるが、酸化チタンのＴｉＯ２ 重量基準に対して、アルミニウム化合物をアルミニウム（Ａｌ）基準に、リン化合物をリン（Ｐ）基準にそれぞれ換算した合量が、好ましくは０．０１〜１重量％、より好ましくは０．０１〜０．８重量％、もっとも好ましくは０．０１〜０．５重量％である。アルミニウム化合物とリン化合物の合量が０．０１重量％より少なかったり、また、１重量％より多かったりすると光触媒機能が低下する場合があるため、好ましくない。アルミニウム化合物および／またはリン化合物を含有させる場合のカリウム化合物の含有量は、前記と同様に、酸化チタンのＴｉＯ２ 重量基準に対して、好ましくは０．０１〜１０重量％、より好ましくは０．０３〜５重量％、もっとも好ましくは０．０５〜３重量％である。アルミニウム化合物および／またはリン化合物を含有させるには、アルミニウム化合物、リン化合物を酸化チタンと混合したり、酸化チタンの粒子表面に担持あるいは被覆したり、酸化チタンの粒子内部にドープしたりすることができる。本発明においては、アルミニウム化合物および／またはリン化合物がカリウム化合物とともに、酸化チタンの粒子内部および／または酸化チタンの粒子表面に存在している状態、特に、アルミニウム化合物および／またはリン化合物が酸化チタンの粒子表面に存在し、カリウム化合物が酸化チタンの粒子内部に少なくとも存在している状態が好ましい。
【０００８】
なお、本発明においては、カリウム化合物あるいは必要に応じてアルミニウム化合物および／またはリン化合物のほかに銅、亜鉛、バナジウム、鉄、コバルト、ニッケル、ルテニウム、ロジウム、パラジウム、銀、金、白金などの金属またはそれらの化合物を酸化チタン光触媒に含有させてもよい。
【０００９】
カリウム化合物が酸化チタンの粒子内部および／または酸化チタンの粒子表面に含有してなる、本発明の光触媒を製造するには、▲１▼カリウム化合物の溶液を酸化チタンあるいは酸化チタンを保持した支持体に浸漬してカリウム化合物を酸化チタンの粒子表面に存在させる方法、▲２▼カリウム化合物の存在下、硫酸チタン、硫酸チタニル、硫酸チタン、塩化チタン、有機チタン化合物などのチタン化合物を、必要に応じてさらに核形成用種子の存在下に、加水分解あるいは中和してカリウム化合物を酸化チタンの粒子内部および／またはその粒子表面に存在させる方法、▲３▼前記▲１▼、▲２▼の方法で得た生成物を５００〜９００℃の温度で焼成する方法が好ましい。特に前記▲１▼の方法で得た生成物を５００〜９００℃の温度で焼成すると、カリウム化合物を酸化チタンの粒子内部に少なくとも存在させることができるため好ましい方法である。
【００１０】
本発明においては、前記の▲１▼〜▲３▼の方法において得られた生成物を本発明の光触媒として用いることができるが、必要に応じて、該生成物を分別したり、洗浄したり、乾燥したりしてもよい。
【００１１】
カリウム化合物と酸化チタンのほかに、アルミニウム化合物および／またはリン化合物を含有してなる光触媒を製造するには前記のカリウム化合物と酸化チタンとを含有してなる光触媒の製造方法に準じた方法で行うことができる。すなわち、前記▲１▼〜▲３▼の方法において、カリウム化合物とともに、アルミニウム化合物および／またはリン化合物を用いるとよい。特に、本発明においては、前記▲１▼、▲２▼の方法に準じて得た、アルミニウム化合物および／またはリン化合物とカリウム化合物と酸化チタンとの生成物を５００〜９００℃の温度で焼成すると、アルミニウム化合物、リン化合物、カリウム化合物を酸化チタンの粒子内部および／または酸化チタンの粒子表面に存在させることができ、特に、アルミニウム化合物、リン化合物を酸化チタンの粒子表面に存在させ、カリウム化合物を酸化チタンの粒子内部に存在させることができるため好ましい方法である。
【００１２】
本発明の光触媒を、有機物質の合成反応や有害物質の分解反応などの種々の光触媒反応に用いるには、それらの処理対象物質の存在下、本発明の光触媒に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。本発明の光触媒は、使用場面に応じて、溶媒に懸濁した状態、光触媒を粉末の状態、あるいは該粉末を粉砕した状態、さらには、該粉末を成形した状態で用いることができる。本発明の光触媒により分解あるいは酸化して除去する有害物質としては、人体や生活環境に悪影響を及ぼす物質やその可能性がある物質であり、たとえば、種々の生物学的酸素要求物質、大気汚染物質などの環境汚染物質や除草剤、殺菌剤、殺虫剤、殺線虫剤などの種々の農薬などの物質、細菌、放線菌、菌類、藻類、カビ類などの微生物などが挙げられる。環境汚染物質としては、有機ハロゲン化合物、有機リン化合物やそれ以外の有機化合物、窒素化合物、硫黄化合物、シアン化合物、クロム化合物などの無機化合物が挙げられる。有機ハロゲン化合物としては、具体的には、ポリ塩化ビフェニル、フロン、トリハロメタン、トリクロロエチレン、テトラクロロエチレンが例示できる。有機ハロゲン化合物、有機リン化合物以外の有機物質としては、具体的には、界面活性剤や油類などの炭化水素類、アルデヒド類、メルカプタン類、アルコール類、アミン類、アミノ酸、蛋白質が例示できる。また、窒素化合物としては、具体的には、アンモニア、窒素酸化物が例示できる。バンドギャップ以上のエネルギーを持つ波長の光としては、紫外線を含有した光が好ましく、たとえば、太陽光や蛍光灯、ブラックライト、ハロゲンランプ、キセノンフラッシュランプ、水銀灯などの光を用いることができる。特に、３００〜４００ｎｍの近紫外線を含有した光が好ましい。光の照射量や照射時間などは処理対象物質の量などによって適宜設定できる。
【００１３】
【実施例】
以下に本発明の実施例を示すが、本発明はこれに限定されるものではない。
実施例１
２．５モル／リットルの硫酸チタニル水溶液を９０℃、３時間保持して加水分解した。このようにして得た加水分解物を濾過し、洗浄した後、１１０℃、５時間乾燥して、酸化チタン（試料１）を得た。
なお、試料１のＳｃｈｅｒｒｅｒの式から求めた平均粒子径は６ｎｍであった。
【００１４】
前記の試料１をＴｉＯ２ に換算して１００ｇ／リットルの懸濁液とし、次いで、このＴｉＯ２ に対して、カリウム（Ｋ）が１．０重量％に相当する量の水酸化カリウムを添加し、攪拌した後、１１０℃で蒸発乾固した。このようにして得た生成物を６００℃、１時間焼成して、本発明の光触媒（試料Ａ）を得た。
なお、試料Ａはカリウム化合物が酸化チタンの粒子表面に存在していると推察された。また、試料ＡのＳｃｈｅｒｒｅｒの式から求めた平均粒子径は２２ｎｍであった。
【００１５】
実施例２
実施例１において、焼成温度を８００℃としたこと以外は、実施例１と同様に処理して、本発明の光触媒（試料Ｂ）を得た。
なお、試料Ｂはカリウム化合物が少なくとも酸化チタンの粒子内部に存在していると推察された。また、試料ＢのＳｃｈｅｒｒｅｒの式から求めた平均粒子径は５７ｎｍであった。
【００１６】
実施例３
前記の試料１をＴｉＯ２ に換算して１００ｇ／リットルの懸濁液とし、次いで、このＴｉＯ２ に対して、カリウム（Ｋ）が０．３重量％、アルミニウム（Ａｌ）が０．０３重量％、リン（Ｐ）が０．２重量％に相当する量の水酸化カリウム、硫酸アルミニウム（Ａｌ２ （ＳＯ４ ）３ ）、リン酸（Ｈ３ ＰＯ４ ）をそれぞれ添加し、攪拌した後、１１０℃で蒸発乾固した。このようにして得た生成物を６００℃、１時間焼成して、本発明の光触媒（試料Ｃ）を得た。
なお、試料Ｃはカリウム化合物、アルミニウム化合物とリン化合物とが酸化チタンの粒子表面に存在していると推察された。また、試料ＣのＳｃｈｅｒｒｅｒの式から求めた平均粒子径は１８ｎｍであった。
【００１７】
実施例４
実施例３において、焼成温度を８００℃としたこと以外は、実施例３と同様に処理して、本発明の光触媒（試料Ｄ）を得た。
なお、試料Ｄはカリウム化合物が少なくとも酸化チタンの粒子内部に存在し、アルミニウム化合物とリン化合物とが酸化チタンの粒子表面に存在していると推察された。また、試料ＤのＳｃｈｅｒｒｅｒの式から求めた平均粒子径は３０ｎｍであった。
【００１８】
比較例１
前記の試料１を比較試料Ｅとして用いた。
【００１９】
比較例２
前記の試料１を３００℃、１時間焼成して、比較試料Ｆを得た。
なお、試料ＦのＳｃｈｅｒｒｅｒの式から求めた平均粒子径は１２ｎｍであった。
【００２０】
比較例３
前記の試料１を６００℃、１時間焼成して、比較試料Ｇを得た。
なお、試料ＧのＳｃｈｅｒｒｅｒの式から求めた平均粒子径は２４ｎｍであった。
【００２１】
比較例４
前記の試料１を８００℃、１時間焼成して、比較試料Ｈを得た。
なお、試料ＨのＳｃｈｅｒｒｅｒの式から求めた平均粒子径は５２ｎｍであった。
【００２２】
比較例５
前記の試料１をＴｉＯ２ に換算して１００ｇ／リットルの懸濁液とし、次いで、このＴｉＯ２ に対して、アルミニウム（Ａｌ）が０．０３重量％に相当する量の硫酸アルミニウム（Ａｌ２ （ＳＯ４ ）３ ）を添加し、攪拌した後、１１０℃で蒸発乾固した。このようにして得た生成物を６００℃、１時間焼成して、比較試料Ｉを得た。
なお、試料ＩのＳｃｈｅｒｒｅｒの式から求めた平均粒子径は２３ｎｍであった。
【００２３】
比較例６
前記の試料１をＴｉＯ２ に換算して１００ｇ／リットルの懸濁液とし、次いで、このＴｉＯ２ に対してリン（Ｐ）が０．２重量％に相当する量のリン酸（Ｈ３ ＰＯ４ ）を添加し、攪拌した後、１１０℃で蒸発乾固した。このようにして得た生成物を６００℃、１時間焼成して、比較試料Ｊを得た。
なお、試料ＪのＳｃｈｅｒｒｅｒの式から求めた平均粒子径は１８ｎｍであった。
【００２４】
実施例および比較例で得られた試料（Ａ〜Ｊ）の光触媒機能を以下のようにして調べた。
各試料０．１ｇを純水に分散させ、ＴｉＯ２ に換算して４ｇ／リットルの懸濁液とした。これらの懸濁液２５ｍｌに２−プロパノール２５ｍｌを添加した後、ブラックライト（ピーク波長３６５ｎｍ）を２時間照射して２−プロパノールの光触媒反応を行った。光量は２ｍＷ／ｃｍ２ であった。反応前の２−プロパノールと反応後の２−プロパノールの濃度から、各々の試料による分解速度を算出した。その結果を表１に示す。
【００２５】
【表１】
また、実施例および比較例で得られた試料（Ｄ、Ｈ）のアンモニアおよび／またはアンモニウムイオンを含有した水溶液の処理試験を行った。すなわち、ＮＨ３ およびＮＨ４ ＋ の合計濃度が１．６７ｍｍｏｌ／ｌの液（ｐＨ＝７．０）２５０ｍｌに試料を１ｇ入れ懸濁液とした。この懸濁液に１００Ｗ高圧水銀ランプから放射する紫外線を照射した。なお、照射面積は１３７．４ｃｍ２ であり、試料に照射される平均光量は４１ｍＷ／ｃｍ２ であった。紫外線を５時間照射して、反応前のＮＨ３ およびＮＨ４ ＋ の合計濃度と反応後のそれとから、各々の試料による分解速度を算出した。その結果を表２に示す。
【００２７】
【表２】
これらの結果から明らかなように、本発明の光触媒は優れた光触媒機能を有し、かつ、熱による光触媒機能の劣化が少ないことがわかった。特に、カリウム化合物が少なくとも酸化チタンの粒子内部に存在すると優れた光触媒機能を有することがわかった。この結果より、本発明の光触媒は、熱による光触媒機能の劣化が少ないことから、本発明の光触媒を焼成して支持体に固定する場合にも好適なものであることがわかった。
【００２９】
本発明の光触媒を支持体に固定化するには、酸化チタンとカリウム化合物と、さらには、必要に応じてアルミニウム化合物および／またはリン化合物とを接触させて生成物を得、次いで、該生成物を支持体に付着させ、しかるのち、５００〜９００℃の温度で焼成する方法が簡便であることから好ましい方法である。
前記の生成物を支持体に付着させるには、生成物の懸濁液を調整し、ディップコーティング法、スプレーコーティング法、スピナーコーティング法、ブレードコーティング法、ローラーコーティング法、ワイヤーバーコーティング法、リバースロールコーティング法などの通常の方法で生成物の懸濁液を支持体上に塗布し、必要に応じて乾燥する方法が好ましい。生成物の懸濁液を調整する際には、生成物を硝酸、塩酸などの一塩基酸で解膠したり、水酸化ナトリウム、水酸化アンモニウム、モノエタノールアミンなどのアルカリで分散させるのが好ましい。本発明の光触媒を固定化する支持体は、使用目的、用途などに応じて材質、形状、大きさを適宜選択することができる。材質としては、たとえば、ガラス、金属、セラミックスなどが挙げられ、形状、大きさとしては、たとえば、１枚の厚板、小さな断片、ビーズのような球状体、多孔質体などが挙げられる。光触媒を支持体に固定化するための焼成の温度は、好ましくは２００〜１０００℃、より好ましくは４００〜９００℃、もっとも好ましくは５００〜９００℃である。焼成温度が５００〜９００℃の範囲であれば、光触媒を支持体に強固に固定化することができるとともに、優れた光触媒機能を有する光触媒体を得ることができる。
【００３０】
【発明の効果】
本発明は、カリウム化合物が酸化チタン粒子の内部および／またはその表面に含有してなる光触媒であって、カリウム化合物を酸化チタン粒子の内部および／またはその表面に含有させることにより酸化チタンの光触媒機能を向上させ、優れた光触媒機能を有し、かつ、熱による光触媒機能の劣化が少ない酸化チタン光触媒とすることができる。
【００３１】
また、本発明はカリウム化合物と酸化チタンのほか、アルミニウム化合物および／またはリン化合物を含有させることにより酸化チタンの光触媒機能を向上させ、優れた光触媒機能を有し、かつ、熱による光触媒機能の劣化が少ない酸化チタン光触媒とすることができる。特に、アルミニウム化合物および／またはリン化合物とカリウム化合物とを酸化チタン粒子の内部および／またはその表面に含有させると、より一層酸化チタンの光触媒機能を向上させることができるため、好ましい実施態様である。
【００３２】
これらの光触媒は、それらの光触媒機能を利用して人体や生活環境に悪影響を及ぼす物質やその可能性がある物質を迅速、かつ、効率よく除去することができるので、工業用途ばかりではなく一般家庭用の脱臭体、殺菌体などとして極めて有用なものである。また、本発明の光触媒は、安全性が高く、さらに、廃棄しても環境を汚さないため、種々の用途に用いることができる。
【００３３】
さらに、本発明は、酸化チタンとカリウム化合物と、さらには必要に応じてアルミニウム化合物および／またはリン化合物とを接触させて生成物を得、次いで、該生成物を５００〜９００℃の温度で焼成する光触媒の製造方法であって、優れた光触媒機能を有する光触媒を簡便に製造することができる。
【００３４】
さらに、本発明の光触媒を支持体に固定化するには、酸化チタンとカリウム化合物と、さらに必要に応じてアルミニウム化合物および／またはリン化合物とを接触させて生成物を得、次いで、該生成物を支持体に付着させ、５００〜９００℃の温度で焼成する固定化した光触媒の製造方法であって、優れた光触媒機能を有する固定化光触媒を簡便に製造することができる。[0001]
[Industrial applications]
The present invention relates to a photocatalyst having an excellent photocatalytic function and a method for producing the same.
[0002]
[Prior art]
When the photocatalyst is irradiated with light having a wavelength having energy equal to or greater than the band gap, photoexcitation generates electrons in the conduction band and holes in the valence band. The strong reducing power of electrons and the strong oxidizing power of holes generated by the photoexcitation are used for reactions such as decomposition and purification of harmful substances, decomposition of water, sterilization, and synthesis of organic substances. For example, Japanese Patent Publication No. 2-9850 describes that a photocatalyst is used to decompose and purify harmful substances in waste. Further, Japanese Patent Publication No. 4-78326 describes that a photocatalyst is used to deodorize toilet odor, pet odor, cigarette odor, cooking odor, body odor and the like. Further, Japanese Patent Publication No. 29393/1990 describes that a predetermined voltage generated by light excitation is applied to a cell to kill the cell.
[0003]
[Problems to be solved by the invention]
In order to use the photocatalyst in the actual reaction, it is necessary to prevent the photocatalyst from scattering from the reaction system during the reaction, and it is necessary to separate the photocatalyst from the reaction system after the reaction is completed. Used while fixed on the body. In order to fix the photocatalyst, a method of adhering the photocatalyst to a support and then calcining at a temperature of 200 to 1000 ° C is usually employed. However, when the photocatalyst is fired at a high temperature, there is a problem that the photocatalytic function is remarkably reduced as compared with that before firing.
In addition, photocatalysts that do not decrease in photocatalytic function even at high temperature conditions have been demanded because photocatalysts are increasingly used in high-temperature reactions, and furthermore, a method of firing at high temperatures when regenerating photocatalysts is considered. ing.
Further, in order to shorten the reaction time and to reduce the size of the apparatus used for the reaction, a photocatalyst having a more excellent photocatalytic function has been long desired.
[0004]
[Means for Solving the Problems]
The present inventors have studied to obtain a titanium oxide photocatalyst with less deterioration of the photocatalytic function due to high-temperature sintering and reaction conditions. As a result, (1) to contain a potassium compound inside and / or on the surface of titanium oxide particles (2) that a more preferable photocatalyst can be obtained by adding an aluminum compound and / or a phosphorus compound and a potassium compound to titanium oxide, and (3) the above (1) and (2). In order to produce the photocatalyst, the titanium oxide, the potassium compound and, if necessary, the aluminum compound and / or the phosphorus compound are brought into contact with each other to obtain a product. (4) In order to immobilize the photocatalyst of the present invention on a support, titanium oxide and potassium must be used. Contacting the compound with, if necessary, an aluminum compound and / or a phosphorus compound to obtain a product, then attaching the product to a support, and then calcining at a temperature of 500 to 900 ° C The inventors have found that the method is simple and preferable, and have completed the present invention.
[0005]
That is, the present invention is to provide a titanium oxide photocatalyst having an excellent photocatalytic function.
[0006]
The present invention is a titanium oxide photocatalyst containing a potassium compound inside and / or on the surface of titanium oxide particles. In the present invention, titanium oxide means various titanium oxides such as anatase-type titanium oxide, rutile-type titanium oxide, amorphous titanium oxide, metatitanic acid, and orthotitanic acid or titanium hydroxide, hydrous titanium oxide, and hydrated titanium oxide. I do. The average particle diameter of the titanium oxide is preferably from 1 to 500 nm, more preferably from 5 to 250 nm, and most preferably from 5 to 100 nm, calculated from the Scherrer's formula. In the present invention, the potassium compound includes compounds such as oxides, hydroxides, sulfates, halides, and nitrates of potassium, and further includes potassium ions. The content of potassium can be appropriately set, but is preferably 0.01 to 10% by weight, more preferably 0.1 to 10% by weight, when the potassium compound is converted to potassium (K) based on TiO 2 weight based on titanium oxide. It is from 03 to 5% by weight, most preferably from 0.05 to 3% by weight. If the amount of the potassium compound is less than 0.01% by weight or more than 10% by weight, the photocatalytic function may deteriorate, which is not preferable. The titanium oxide photocatalyst of the present invention is different from a mere mixture of titanium oxide and a potassium compound, in which the potassium compound is carried or coated on the surface of the titanium oxide particles, or the potassium compound is doped inside the titanium oxide particles. This is a particle that maintains a state in which a potassium compound is present inside the titanium oxide particles and / or on the surface of the titanium oxide particles, in particular, a state where it is present at least inside the titanium oxide particles.
[0007]
Further, the present invention is a titanium oxide photocatalyst comprising an aluminum compound and / or a phosphorus compound and a potassium compound. In the present invention, the aluminum compound includes compounds such as aluminum oxides, hydroxides, sulfates, halides, and nitrates, and further includes aluminum ions. In addition, a phosphorus compound includes phosphorus oxide, phosphoric acid or a salt thereof, condensed phosphoric acid or a salt thereof, phosphinic acid or a salt thereof, phosphonic acid or a salt thereof, diphosphonic acid or a salt thereof, hypophosphoric acid or a salt thereof, and the like. And further contains a phosphate ion. The content of the aluminum compound and / or the phosphorus compound can be appropriately set, but the aluminum compound is converted to the aluminum (Al) standard and the phosphorus compound is converted to the phosphorus (P) standard with respect to the weight of TiO 2 of titanium oxide. The total amount is preferably 0.01 to 1% by weight, more preferably 0.01 to 0.8% by weight, and most preferably 0.01 to 0.5% by weight. If the total amount of the aluminum compound and the phosphorus compound is less than 0.01% by weight or more than 1% by weight, the photocatalytic function may be reduced, which is not preferable. As described above, the content of the potassium compound when the aluminum compound and / or the phosphorus compound is contained is preferably 0.01 to 10% by weight, more preferably 0.1 to 10% by weight, based on the weight of TiO 2 of titanium oxide. It is from 03 to 5% by weight, most preferably from 0.05 to 3% by weight. In order to contain the aluminum compound and / or the phosphorus compound, the aluminum compound and the phosphorus compound may be mixed with titanium oxide, supported or coated on the surface of the titanium oxide particles, or doped inside the titanium oxide particles. it can. In the present invention, the aluminum compound and / or the phosphorus compound are present together with the potassium compound inside the titanium oxide particles and / or on the surface of the titanium oxide particles. It is preferable that the compound is present on the particle surface and the potassium compound is present at least inside the titanium oxide particle.
[0008]
In the present invention, a metal such as copper, zinc, vanadium, iron, cobalt, nickel, ruthenium, rhodium, palladium, silver, gold, platinum or the like, in addition to a potassium compound or an aluminum compound and / or a phosphorus compound as required. Alternatively, those compounds may be contained in a titanium oxide photocatalyst.
[0009]
In order to produce the photocatalyst of the present invention in which the potassium compound is contained inside the titanium oxide particles and / or on the surface of the titanium oxide particles, (1) a solution of the potassium compound is made of titanium oxide or a support holding titanium oxide. (2) a titanium compound such as titanium sulfate, titanyl sulfate, titanium sulfate, titanium chloride, or an organic titanium compound, if necessary, in the presence of the potassium compound. A potassium compound is present inside and / or on the surface of titanium oxide particles by hydrolysis or neutralization in the presence of seeds for nucleation, and (3) the method of (1) or (2) above. The method of baking the product obtained in the above at a temperature of 500 to 900 ° C. is preferred. In particular, when the product obtained by the method (1) is calcined at a temperature of 500 to 900 ° C., the potassium compound can be present at least inside the titanium oxide particles, which is a preferable method.
[0010]
In the present invention, the product obtained by the above methods (1) to (3) can be used as the photocatalyst of the present invention. However, if necessary, the product may be separated or washed. , And may be dried.
[0011]
In order to produce a photocatalyst containing an aluminum compound and / or a phosphorus compound in addition to a potassium compound and titanium oxide, a method similar to the above-mentioned method for producing a photocatalyst containing a potassium compound and titanium oxide is used. be able to. That is, in the methods (1) to (3), an aluminum compound and / or a phosphorus compound may be used together with the potassium compound. In particular, in the present invention, when a product of an aluminum compound and / or a phosphorus compound, a potassium compound, and titanium oxide obtained according to the above methods (1) and (2) is fired at a temperature of 500 to 900 ° C. , An aluminum compound, a phosphorus compound, and a potassium compound can be present inside the titanium oxide particles and / or on the surface of the titanium oxide particles. In particular, when the aluminum compound and the phosphorus compound are present on the titanium oxide particles, This is a preferable method because it can be present inside the titanium oxide particles.
[0012]
In order to use the photocatalyst of the present invention for various photocatalytic reactions such as a synthesis reaction of an organic substance and a decomposition reaction of a harmful substance, the photocatalyst of the present invention has energy equal to or more than its band gap in the presence of the substance to be treated. Irradiate light of wavelength. The photocatalyst of the present invention can be used in a state suspended in a solvent, a state in which the photocatalyst is in a powder state, a state in which the powder is crushed, or a state in which the powder is formed, depending on the use scene. The harmful substances that are decomposed or oxidized and removed by the photocatalyst of the present invention include substances that have a negative effect on the human body and living environment, and substances that may cause such harmful substances. For example, various biological oxygen demanding substances, air pollutants Examples of such substances include environmental pollutants, such as herbicides, fungicides, insecticides, and various pesticides such as nematicides, and microorganisms such as bacteria, actinomycetes, fungi, algae, and molds. Examples of the environmental pollutants include organic halogen compounds, organic phosphorus compounds and other organic compounds, and inorganic compounds such as nitrogen compounds, sulfur compounds, cyanide compounds, and chromium compounds. Specific examples of the organic halogen compound include polychlorinated biphenyl, freon, trihalomethane, trichloroethylene, and tetrachloroethylene. Specific examples of the organic substance other than the organic halogen compound and the organic phosphorus compound include hydrocarbons such as surfactants and oils, aldehydes, mercaptans, alcohols, amines, amino acids, and proteins. In addition, specific examples of the nitrogen compound include ammonia and nitrogen oxides. As light having a wavelength having an energy equal to or greater than the band gap, light containing ultraviolet light is preferable. For example, light from sunlight, a fluorescent lamp, a black light, a halogen lamp, a xenon flash lamp, a mercury lamp, or the like can be used. In particular, light containing near-ultraviolet light of 300 to 400 nm is preferable. The irradiation amount and irradiation time of light can be appropriately set depending on the amount of the substance to be treated.
[0013]
【Example】
Examples of the present invention will be described below, but the present invention is not limited to these examples.
Example 1
A 2.5 mol / liter aqueous solution of titanyl sulfate was hydrolyzed at 90 ° C. for 3 hours. The hydrolyzate thus obtained was filtered, washed, and dried at 110 ° C. for 5 hours to obtain titanium oxide (sample 1).
The average particle diameter of Sample 1 determined from the Scherrer equation was 6 nm.
[0014]
Sample 1 was converted into a suspension of 100 g / liter in terms of TiO 2 , and then potassium hydroxide was added to the TiO 2 in an amount corresponding to 1.0% by weight of potassium (K). After stirring, the mixture was evaporated to dryness at 110 ° C. The product thus obtained was calcined at 600 ° C. for 1 hour to obtain a photocatalyst (sample A) of the present invention.
In addition, in sample A, it was inferred that the potassium compound was present on the surface of the titanium oxide particles. The average particle size of Sample A determined from the Scherrer's equation was 22 nm.
[0015]
Example 2
A photocatalyst of the present invention (sample B) was obtained in the same manner as in Example 1, except that the firing temperature was changed to 800 ° C.
Sample B was presumed to contain a potassium compound at least inside the titanium oxide particles. The average particle size of Sample B determined from the Scherrer's equation was 57 nm.
[0016]
Example 3
The above sample 1 was converted into a suspension of 100 g / liter in terms of TiO 2 , and then 0.3% by weight of potassium (K) and 0.03% by weight of aluminum (Al) based on the TiO 2 . , Potassium hydroxide, aluminum sulfate (Al 2 (SO 4 ) 3 ), and phosphoric acid (H 3 PO 4 ) in an amount corresponding to 0.2% by weight of phosphorus (P) were added, and the mixture was stirred. Evaporated to dryness at ℃. The product thus obtained was calcined at 600 ° C. for 1 hour to obtain a photocatalyst (sample C) of the present invention.
In sample C, it was assumed that a potassium compound, an aluminum compound and a phosphorus compound were present on the surface of the titanium oxide particles. The average particle size of Sample C determined from the Scherrer's equation was 18 nm.
[0017]
Example 4
A photocatalyst of the present invention (sample D) was obtained in the same manner as in Example 3, except that the calcination temperature was changed to 800 ° C.
In sample D, it was inferred that the potassium compound was present at least inside the titanium oxide particles, and the aluminum compound and the phosphorus compound were present on the surface of the titanium oxide particles. The average particle diameter of Sample D determined from the Scherrer's equation was 30 nm.
[0018]
Comparative Example 1
Sample 1 described above was used as Comparative Sample E.
[0019]
Comparative Example 2
The sample 1 was fired at 300 ° C. for 1 hour to obtain a comparative sample F.
The average particle size of Sample F determined by the Scherrer equation was 12 nm.
[0020]
Comparative Example 3
The sample 1 was fired at 600 ° C. for 1 hour to obtain a comparative sample G.
The average particle size of Sample G determined by Scherrer's equation was 24 nm.
[0021]
Comparative Example 4
The sample 1 was fired at 800 ° C. for 1 hour to obtain a comparative sample H.
The average particle size of Sample H determined from the Scherrer's equation was 52 nm.
[0022]
Comparative Example 5
A suspension of 100 g / liter in terms of the sample 1 of the on TiO 2, then, for this TiO 2, the amount of aluminum sulphate aluminum (Al) is equivalent to 0.03 wt% (Al 2 ( After adding SO 4 ) 3 ) and stirring, it was evaporated to dryness at 110 ° C. The product thus obtained was calcined at 600 ° C. for 1 hour to obtain Comparative Sample I.
The average particle size of Sample I determined by the Scherrer's formula was 23 nm.
[0023]
Comparative Example 6
The above sample 1 was converted into a suspension of 100 g / liter in terms of TiO 2 , and then phosphoric acid (H 3 PO 4 ) was added in an amount corresponding to 0.2% by weight of phosphorus (P) based on the TiO 2 . ) Was added and stirred, and then evaporated to dryness at 110 ° C. The product thus obtained was calcined at 600 ° C. for 1 hour to obtain Comparative Sample J.
The average particle size of Sample J determined by Scherrer's equation was 18 nm.
[0024]
The photocatalytic functions of the samples (A to J) obtained in Examples and Comparative Examples were examined as follows.
Each sample 0.1g is dispersed in pure water to obtain a suspension of 4g / l in terms of TiO 2. After adding 25 ml of 2-propanol to 25 ml of these suspensions, black light (peak wavelength 365 nm) was irradiated for 2 hours to perform a photocatalytic reaction of 2-propanol. The light amount was 2 mW / cm 2 . From the concentrations of 2-propanol before the reaction and 2-propanol after the reaction, the decomposition rate of each sample was calculated. Table 1 shows the results.
[0025]
[Table 1]
In addition, treatment tests of aqueous solutions containing ammonia and / or ammonium ions of the samples (D, H) obtained in Examples and Comparative Examples were performed. That is, 1 g of a sample was placed in 250 ml of a liquid (pH = 7.0) having a total concentration of NH 3 and NH 4 + of 1.67 mmol / l to form a suspension. The suspension was irradiated with ultraviolet rays emitted from a 100 W high-pressure mercury lamp. The irradiation area was 137.4Cm 2, the average amount of light applied to the sample was 41mW / cm 2. Ultraviolet rays were irradiated for 5 hours, and the decomposition rate of each sample was calculated from the total concentration of NH 3 and NH 4 + before the reaction and that after the reaction. Table 2 shows the results.
[0027]
[Table 2]
As is clear from these results, it was found that the photocatalyst of the present invention has an excellent photocatalytic function and that the deterioration of the photocatalytic function by heat is small. In particular, it was found that when the potassium compound was present at least inside the titanium oxide particles, it had an excellent photocatalytic function. From these results, it was found that the photocatalyst of the present invention is suitable for the case where the photocatalyst of the present invention is calcined and fixed to a support, since the photocatalytic function is hardly deteriorated by heat.
[0029]
In order to immobilize the photocatalyst of the present invention on a support, a product is obtained by contacting a titanium oxide and a potassium compound, and further, if necessary, with an aluminum compound and / or a phosphorus compound. Is preferred because it is simple to adhere to a support and then calcined at a temperature of 500 to 900 ° C.
To adhere the product to the support, the suspension of the product is prepared, dip coating method, spray coating method, spinner coating method, blade coating method, roller coating method, wire bar coating method, reverse roll A method in which a product suspension is applied to a support by a usual method such as a coating method, and dried if necessary, is preferred. When preparing a suspension of the product, the product is preferably peptized with a monobasic acid such as nitric acid or hydrochloric acid, or dispersed in an alkali such as sodium hydroxide, ammonium hydroxide or monoethanolamine. . The material, shape and size of the support for immobilizing the photocatalyst of the present invention can be appropriately selected according to the purpose of use, application, and the like. Examples of the material include glass, metal, and ceramics, and examples of the shape and size include a thick plate, a small piece, a spherical body such as beads, and a porous body. The firing temperature for immobilizing the photocatalyst on the support is preferably from 200 to 1000C, more preferably from 400 to 900C, and most preferably from 500 to 900C. When the firing temperature is in the range of 500 to 900 ° C., the photocatalyst can be firmly fixed to the support, and a photocatalyst having an excellent photocatalytic function can be obtained.
[0030]
【The invention's effect】
The present invention relates to a photocatalyst comprising a potassium compound inside and / or on the surface of titanium oxide particles, and a photocatalytic function of titanium oxide by containing a potassium compound inside and / or on the surface of titanium oxide particles. And a titanium oxide photocatalyst having an excellent photocatalytic function and having little deterioration of the photocatalytic function due to heat.
[0031]
In addition, the present invention improves the photocatalytic function of titanium oxide by containing an aluminum compound and / or a phosphorus compound in addition to a potassium compound and titanium oxide, has an excellent photocatalytic function, and deteriorates the photocatalytic function due to heat. With less titanium oxide photocatalyst. In particular, when an aluminum compound and / or a phosphorus compound and a potassium compound are contained inside and / or on the surface of titanium oxide particles, the photocatalytic function of titanium oxide can be further improved, which is a preferred embodiment.
[0032]
These photocatalysts can quickly and efficiently remove substances that have a negative effect on the human body and living environment and substances that have the potential to make use of their photocatalytic functions. It is extremely useful as a deodorant, sterilizer, etc. Further, the photocatalyst of the present invention has high safety and does not pollute the environment even when discarded, so that it can be used for various applications.
[0033]
Furthermore, the present invention provides a product by contacting titanium oxide with a potassium compound and, if necessary, an aluminum compound and / or a phosphorus compound, and then calcining the product at a temperature of 500 to 900 ° C. A photocatalyst having excellent photocatalytic function can be easily produced.
[0034]
Further, in order to immobilize the photocatalyst of the present invention on a support, a product is obtained by contacting titanium oxide with a potassium compound and, if necessary, an aluminum compound and / or a phosphorus compound. Is immobilized on a support and calcined at a temperature of 500 to 900 ° C. to produce an immobilized photocatalyst having an excellent photocatalytic function.
Claims (9)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33945194A JP3567004B2 (en) | 1994-12-29 | 1994-12-29 | Photocatalyst and method for producing the same |
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| Application Number | Priority Date | Filing Date | Title |
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| JP33945194A JP3567004B2 (en) | 1994-12-29 | 1994-12-29 | Photocatalyst and method for producing the same |
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| JPH08182934A JPH08182934A (en) | 1996-07-16 |
| JP3567004B2 true JP3567004B2 (en) | 2004-09-15 |
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| JP4305001B2 (en) * | 1996-09-20 | 2009-07-29 | 株式会社日立製作所 | Articles with a photocatalytic film |
| JP3511832B2 (en) * | 1997-02-21 | 2004-03-29 | 株式会社村田製作所 | Titanium compound for photochemical reaction and method for producing the same |
| JP3863621B2 (en) * | 1997-02-24 | 2006-12-27 | 日東電工株式会社 | Adhesive tape |
| JP3518251B2 (en) * | 1997-05-20 | 2004-04-12 | 株式会社日立製作所 | Oxide photocatalytic thin film and article provided with the same |
| JP3510082B2 (en) * | 1997-05-20 | 2004-03-22 | 株式会社日立製作所 | Electrical products equipped with low-temperature curing type highly active oxide photocatalytic thin films |
| CN1117630C (en) * | 1997-12-25 | 2003-08-13 | 工业技术院 | Photocatalyst powder for environmental purification, polymer composition contg. said powder and molded article thereof, and processes for producing these |
| JP5830527B2 (en) * | 2011-04-04 | 2015-12-09 | 株式会社日立製作所 | Semiconductor device, hydrogen production system, and methane or methanol production system |
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