JP2019171319A - photocatalyst - Google Patents
photocatalyst Download PDFInfo
- Publication number
- JP2019171319A JP2019171319A JP2018064190A JP2018064190A JP2019171319A JP 2019171319 A JP2019171319 A JP 2019171319A JP 2018064190 A JP2018064190 A JP 2018064190A JP 2018064190 A JP2018064190 A JP 2018064190A JP 2019171319 A JP2019171319 A JP 2019171319A
- Authority
- JP
- Japan
- Prior art keywords
- titanium
- photocatalyst
- dispersion
- acid
- titania
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000011941 photocatalyst Substances 0.000 title claims abstract description 43
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 191
- 239000002105 nanoparticle Substances 0.000 claims abstract description 52
- 239000002245 particle Substances 0.000 claims abstract description 31
- 125000002252 acyl group Chemical group 0.000 claims abstract description 26
- 230000004580 weight loss Effects 0.000 claims abstract description 9
- 239000006185 dispersion Substances 0.000 claims description 66
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 51
- 229910052719 titanium Inorganic materials 0.000 claims description 48
- 239000010936 titanium Substances 0.000 claims description 48
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical group [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 34
- 150000007524 organic acids Chemical class 0.000 claims description 34
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 30
- 239000000126 substance Substances 0.000 claims description 24
- -1 titanium alkoxide Chemical class 0.000 claims description 19
- 238000010438 heat treatment Methods 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 13
- 239000007788 liquid Substances 0.000 claims description 12
- 125000004432 carbon atom Chemical group C* 0.000 claims description 11
- 229910052801 chlorine Inorganic materials 0.000 claims description 9
- 150000007522 mineralic acids Chemical class 0.000 claims description 9
- 229910052717 sulfur Inorganic materials 0.000 claims description 9
- 239000002270 dispersing agent Substances 0.000 claims description 8
- 238000005259 measurement Methods 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 7
- 229910052757 nitrogen Inorganic materials 0.000 claims description 7
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 claims description 6
- 239000013078 crystal Substances 0.000 claims description 5
- 125000000217 alkyl group Chemical group 0.000 claims description 4
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 4
- LLZRNZOLAXHGLL-UHFFFAOYSA-J titanic acid Chemical compound O[Ti](O)(O)O LLZRNZOLAXHGLL-UHFFFAOYSA-J 0.000 claims description 4
- 125000002768 hydroxyalkyl group Chemical group 0.000 claims description 3
- 150000001735 carboxylic acids Chemical class 0.000 claims 1
- 239000010419 fine particle Substances 0.000 abstract description 3
- 238000004455 differential thermal analysis Methods 0.000 abstract 1
- 238000002411 thermogravimetry Methods 0.000 abstract 1
- 239000011248 coating agent Substances 0.000 description 25
- 238000000576 coating method Methods 0.000 description 25
- 230000001699 photocatalysis Effects 0.000 description 20
- VXUYXOFXAQZZMF-UHFFFAOYSA-N titanium(IV) isopropoxide Chemical compound CC(C)O[Ti](OC(C)C)(OC(C)C)OC(C)C VXUYXOFXAQZZMF-UHFFFAOYSA-N 0.000 description 19
- 235000011054 acetic acid Nutrition 0.000 description 16
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 12
- 238000006243 chemical reaction Methods 0.000 description 10
- 239000011521 glass Substances 0.000 description 10
- 238000003756 stirring Methods 0.000 description 10
- 239000000758 substrate Substances 0.000 description 10
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 9
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 8
- 239000002904 solvent Substances 0.000 description 7
- 238000002834 transmittance Methods 0.000 description 7
- AEMRFAOFKBGASW-UHFFFAOYSA-N Glycolic acid Chemical compound OCC(O)=O AEMRFAOFKBGASW-UHFFFAOYSA-N 0.000 description 6
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 6
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 6
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 6
- 229910017604 nitric acid Inorganic materials 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 230000007797 corrosion Effects 0.000 description 5
- 238000005260 corrosion Methods 0.000 description 5
- 239000002244 precipitate Substances 0.000 description 5
- RBTBFTRPCNLSDE-UHFFFAOYSA-N 3,7-bis(dimethylamino)phenothiazin-5-ium Chemical compound C1=CC(N(C)C)=CC2=[S+]C3=CC(N(C)C)=CC=C3N=C21 RBTBFTRPCNLSDE-UHFFFAOYSA-N 0.000 description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 4
- 239000002253 acid Substances 0.000 description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 4
- 229960000907 methylthioninium chloride Drugs 0.000 description 4
- 150000002762 monocarboxylic acid derivatives Chemical class 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- ZUHZGEOKBKGPSW-UHFFFAOYSA-N tetraglyme Chemical compound COCCOCCOCCOCCOC ZUHZGEOKBKGPSW-UHFFFAOYSA-N 0.000 description 4
- 238000001132 ultrasonic dispersion Methods 0.000 description 4
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 150000002148 esters Chemical class 0.000 description 3
- 235000019253 formic acid Nutrition 0.000 description 3
- 238000007654 immersion Methods 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 239000004310 lactic acid Substances 0.000 description 3
- 235000014655 lactic acid Nutrition 0.000 description 3
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 3
- 235000005985 organic acids Nutrition 0.000 description 3
- 125000004066 1-hydroxyethyl group Chemical group [H]OC([H])([*])C([H])([H])[H] 0.000 description 2
- VXQBJTKSVGFQOL-UHFFFAOYSA-N 2-(2-butoxyethoxy)ethyl acetate Chemical compound CCCCOCCOCCOC(C)=O VXQBJTKSVGFQOL-UHFFFAOYSA-N 0.000 description 2
- 125000000954 2-hydroxyethyl group Chemical group [H]C([*])([H])C([H])([H])O[H] 0.000 description 2
- FERIUCNNQQJTOY-UHFFFAOYSA-N Butyric acid Chemical compound CCCC(O)=O FERIUCNNQQJTOY-UHFFFAOYSA-N 0.000 description 2
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 125000002777 acetyl group Chemical group [H]C([H])([H])C(*)=O 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- YHWCPXVTRSHPNY-UHFFFAOYSA-N butan-1-olate;titanium(4+) Chemical compound [Ti+4].CCCC[O-].CCCC[O-].CCCC[O-].CCCC[O-] YHWCPXVTRSHPNY-UHFFFAOYSA-N 0.000 description 2
- WERYXYBDKMZEQL-UHFFFAOYSA-N butane-1,4-diol Chemical compound OCCCCO WERYXYBDKMZEQL-UHFFFAOYSA-N 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- XBDQKXXYIPTUBI-UHFFFAOYSA-N dimethylselenoniopropionate Natural products CCC(O)=O XBDQKXXYIPTUBI-UHFFFAOYSA-N 0.000 description 2
- 238000001027 hydrothermal synthesis Methods 0.000 description 2
- 125000004029 hydroxymethyl group Chemical group [H]OC([H])([H])* 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 125000000896 monocarboxylic acid group Chemical group 0.000 description 2
- KELHQGOVULCJSG-UHFFFAOYSA-N n,n-dimethyl-1-(5-methylfuran-2-yl)ethane-1,2-diamine Chemical compound CN(C)C(CN)C1=CC=C(C)O1 KELHQGOVULCJSG-UHFFFAOYSA-N 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000004528 spin coating Methods 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 239000004408 titanium dioxide Substances 0.000 description 2
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 description 2
- YONPGGFAJWQGJC-UHFFFAOYSA-K titanium(iii) chloride Chemical compound Cl[Ti](Cl)Cl YONPGGFAJWQGJC-UHFFFAOYSA-K 0.000 description 2
- 230000001988 toxicity Effects 0.000 description 2
- 231100000419 toxicity Toxicity 0.000 description 2
- 239000013585 weight reducing agent Substances 0.000 description 2
- WUOACPNHFRMFPN-SECBINFHSA-N (S)-(-)-alpha-terpineol Chemical compound CC1=CC[C@@H](C(C)(C)O)CC1 WUOACPNHFRMFPN-SECBINFHSA-N 0.000 description 1
- HYLLZXPMJRMUHH-UHFFFAOYSA-N 1-[2-(2-methoxyethoxy)ethoxy]butane Chemical compound CCCCOCCOCCOC HYLLZXPMJRMUHH-UHFFFAOYSA-N 0.000 description 1
- SNAQINZKMQFYFV-UHFFFAOYSA-N 1-[2-[2-(2-methoxyethoxy)ethoxy]ethoxy]butane Chemical compound CCCCOCCOCCOCCOC SNAQINZKMQFYFV-UHFFFAOYSA-N 0.000 description 1
- RERATEUBWLKDFE-UHFFFAOYSA-N 1-methoxy-2-[2-(2-methoxypropoxy)propoxy]propane Chemical compound COCC(C)OCC(C)OCC(C)OC RERATEUBWLKDFE-UHFFFAOYSA-N 0.000 description 1
- ARXJGSRGQADJSQ-UHFFFAOYSA-N 1-methoxypropan-2-ol Chemical compound COCC(C)O ARXJGSRGQADJSQ-UHFFFAOYSA-N 0.000 description 1
- OAYXUHPQHDHDDZ-UHFFFAOYSA-N 2-(2-butoxyethoxy)ethanol Chemical compound CCCCOCCOCCO OAYXUHPQHDHDDZ-UHFFFAOYSA-N 0.000 description 1
- FPZWZCWUIYYYBU-UHFFFAOYSA-N 2-(2-ethoxyethoxy)ethyl acetate Chemical compound CCOCCOCCOC(C)=O FPZWZCWUIYYYBU-UHFFFAOYSA-N 0.000 description 1
- OHJYHAOODFPJOD-UHFFFAOYSA-N 2-(2-ethylhexoxy)ethanol Chemical compound CCCCC(CC)COCCO OHJYHAOODFPJOD-UHFFFAOYSA-N 0.000 description 1
- XNWFRZJHXBZDAG-UHFFFAOYSA-N 2-METHOXYETHANOL Chemical compound COCCO XNWFRZJHXBZDAG-UHFFFAOYSA-N 0.000 description 1
- OVOUKWFJRHALDD-UHFFFAOYSA-N 2-[2-(2-acetyloxyethoxy)ethoxy]ethyl acetate Chemical compound CC(=O)OCCOCCOCCOC(C)=O OVOUKWFJRHALDD-UHFFFAOYSA-N 0.000 description 1
- DXYGJDUJLDXFOD-UHFFFAOYSA-N 2-[2-[2-(2-acetyloxyethoxy)ethoxy]ethoxy]ethyl acetate Chemical compound CC(=O)OCCOCCOCCOCCOC(C)=O DXYGJDUJLDXFOD-UHFFFAOYSA-N 0.000 description 1
- CRWNQZTZTZWPOF-UHFFFAOYSA-N 2-methyl-4-phenylpyridine Chemical compound C1=NC(C)=CC(C=2C=CC=CC=2)=C1 CRWNQZTZTZWPOF-UHFFFAOYSA-N 0.000 description 1
- 229910002012 Aerosil® Inorganic materials 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- ALQSHHUCVQOPAS-UHFFFAOYSA-N Pentane-1,5-diol Chemical compound OCCCCCO ALQSHHUCVQOPAS-UHFFFAOYSA-N 0.000 description 1
- 229910003088 Ti−O−Ti Inorganic materials 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- OVKDFILSBMEKLT-UHFFFAOYSA-N alpha-Terpineol Natural products CC(=C)C1(O)CCC(C)=CC1 OVKDFILSBMEKLT-UHFFFAOYSA-N 0.000 description 1
- 229940088601 alpha-terpineol Drugs 0.000 description 1
- 239000003125 aqueous solvent Substances 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000012295 chemical reaction liquid Substances 0.000 description 1
- 239000007810 chemical reaction solvent Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- UBPGILLNMDGSDS-UHFFFAOYSA-N diethylene glycol diacetate Chemical compound CC(=O)OCCOCCOC(C)=O UBPGILLNMDGSDS-UHFFFAOYSA-N 0.000 description 1
- 229940028356 diethylene glycol monobutyl ether Drugs 0.000 description 1
- 150000002009 diols Chemical class 0.000 description 1
- 238000003618 dip coating Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000001879 gelation Methods 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- ACCCMOQWYVYDOT-UHFFFAOYSA-N hexane-1,1-diol Chemical compound CCCCCC(O)O ACCCMOQWYVYDOT-UHFFFAOYSA-N 0.000 description 1
- FDVKPDVESAUTEE-UHFFFAOYSA-N hexane-1,6-diol;2-methylpentane-2,4-diol Chemical compound CC(O)CC(C)(C)O.OCCCCCCO FDVKPDVESAUTEE-UHFFFAOYSA-N 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 125000004123 n-propyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- JCGNDDUYTRNOFT-UHFFFAOYSA-N oxolane-2,4-dione Chemical compound O=C1COC(=O)C1 JCGNDDUYTRNOFT-UHFFFAOYSA-N 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 235000019260 propionic acid Nutrition 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- IUVKMZGDUIUOCP-BTNSXGMBSA-N quinbolone Chemical compound O([C@H]1CC[C@H]2[C@H]3[C@@H]([C@]4(C=CC(=O)C=C4CC3)C)CC[C@@]21C)C1=CCCC1 IUVKMZGDUIUOCP-BTNSXGMBSA-N 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000007650 screen-printing Methods 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- JMXKSZRRTHPKDL-UHFFFAOYSA-N titanium ethoxide Chemical compound [Ti+4].CC[O-].CC[O-].CC[O-].CC[O-] JMXKSZRRTHPKDL-UHFFFAOYSA-N 0.000 description 1
- YFNKIDBQEZZDLK-UHFFFAOYSA-N triglyme Chemical compound COCCOCCOCCOC YFNKIDBQEZZDLK-UHFFFAOYSA-N 0.000 description 1
- 238000000870 ultraviolet spectroscopy Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Landscapes
- Catalysts (AREA)
Abstract
Description
本発明は、光触媒に関する。 The present invention relates to a photocatalyst.
チタニア（酸化チタン）は光触媒材料として利用されている。一般的にはチタニアの粉体を溶媒に分散して使用されている。 Titania (titanium oxide) is used as a photocatalytic material. In general, titania powder is dispersed in a solvent.
光触媒用のチタニアに関しては、結晶性が高いものが多く、結晶性が高いほどチタニアの屈折率が高いがゆえに、白色度が非常に強く透明性に劣るものが多かった。 Many titania for photocatalysts have high crystallinity, and the higher the crystallinity, the higher the refractive index of titania. Therefore, the whiteness is very strong and the transparency is often inferior.
一方、粒径が小さいほど水やアルコール中では凝集してしまい、均一に塗布しにくいうえに、結局透明性が出ない。また、仮に塗布しても、平均粒子径が小さいほど乾燥による収縮が大きいためクラックや剥がれが起こりやすい。また、樹脂に塗布した場合は樹脂を劣化させてしまう。 On the other hand, the smaller the particle size, the more agglomerates in water and alcohol, the more difficult it is to apply uniformly, and the end result is no transparency. Even if it is applied temporarily, cracks and peeling tend to occur because the shrinkage due to drying increases as the average particle size decreases. Moreover, when it apply | coats to resin, resin will deteriorate.
一方、有機系の分散剤を用いた場合は、チタニア表面の活性が損なわれるという問題点がある。また硝酸や塩酸等の無機強酸を用いて分散した場合は、分散性は向上するが酸の揮発により周辺の装置を腐食してしまうという問題がある。 On the other hand, when an organic dispersant is used, there is a problem that the activity of the titania surface is impaired. Further, when dispersed using a strong inorganic acid such as nitric acid or hydrochloric acid, the dispersibility is improved, but there is a problem that the surrounding apparatus is corroded by the volatilization of the acid.
また、チタンアルコキシド等のチタン源と硝酸や塩酸等の無機強酸を用いて水熱合成反応を行う方法（非特許文献１等）もあるが、工業的には排水の問題や反応器の腐食の問題が起こる恐れがあるため、硝酸や塩酸を用いることができない場合が多い。 There is also a method of hydrothermal synthesis reaction using a titanium source such as titanium alkoxide and an inorganic strong acid such as nitric acid or hydrochloric acid (Non-Patent Document 1 etc.). In many cases, nitric acid or hydrochloric acid cannot be used because problems may occur.
そこで、本発明は、大きいチタニア粒子でも小さいチタニア粒子でも達成できなかった塗布性、光触媒性及び透明性を備えたチタニア微粒子を得ることを目的とする。 Therefore, an object of the present invention is to obtain titania fine particles having coating properties, photocatalytic properties, and transparency that could not be achieved with either large titania particles or small titania particles.
上記目的を鑑み、鋭意検討した結果、本発明者らは、表面にアシル基が結合しており、且つ、示差熱熱重量同時測定装置によって昇温させた場合の200℃以上における重量減少が5重量%以上であるチタニアナノ粒子が、上記課題を全て解決できることを見出した。そして、さらに研究を重ね、本発明を完成させた。すなわち、本発明は、以下の構成を包含する。
項１．チタニアナノ粒子を含有する光触媒であって、前記チタニアナノ粒子は、表面にアシル基が結合しており、且つ、示差熱熱重量同時測定装置によって600℃まで昇温させた場合の200℃以上における重量減少が5重量%以上である、光触媒。
項２．前記アシル基が、-OCOR（式中、Rは水素原子、炭素数1〜3のアルキル基、又は炭素数1〜2のヒドロキシアルキル基を示す）で表される基でチタン原子と結合している、項１に記載の光触媒。
項３．前記アシル基が、炭素数1〜4のモルカルボン酸及び炭素数2〜3のヒドロキシカルボン酸よりなる群から選ばれる少なくとも1種の有機酸由来のアシル基である、項１に記載の光触媒。
項４．前記有機酸が酢酸である、項３に記載の光触媒。
項５．前記チタニアナノ粒子の平均粒子径が1〜5nmである、項１〜４のいずれか1項に記載の光触媒。
項６．前記チタニアナノ粒子の比表面積が150〜500m2/gである、項１〜５のいずれか1項に記載の光触媒。
項７．前記チタニアナノ粒子がアナターゼ型以外の結晶形を含まない、項１〜６のいずれか1項に記載の光触媒。
項８．項１〜７のいずれか1項に記載の光触媒の製造方法であって、
（A）チタンを含む物質、有機酸及び水を混合して分散液を得る工程、及び
（B）前記工程（A）で得られた分散液を80℃より高い温度で1時間以上加熱する工程
を備え、且つ、
前記工程（A）において、前記チタンを含む物質と前記有機酸との混合比率は、前記チタンを含む物質中のチタン1モルに対して前記有機酸中のアシル基が1.5モル以上である、製造方法。
項９．前記工程（B）における加熱条件が82℃以上で1.5時間以上である、項８に記載の製造方法。
項１０．前記チタンを含む物質がチタンアルコキシド、水酸化チタン又はハロゲン化チタンである、項８又は９に記載の製造方法。
項１１．工程（A）において作製される分散液中のN、Cl及びS元素の濃度がいずれも0.01mol/L以下である、項８〜１０のいずれか1項に記載の製造方法。
項１２．工程（A）において作製される分散液中の無機酸の濃度が0.01mol/L以下である、項８〜１１のいずれか1項に記載の製造方法。
項１３．工程（B）において作製される分散液のpHが2以上6未満である、項８〜１２のいずれか1項に記載の製造方法。
項１４．水50質量%以上と、項１〜７のいずれか1項に記載の光触媒とを含有する、光触媒分散液。
項１５．前記有機酸とは別途有機分散剤を含有しない、項１４に記載の光触媒分散液。
As a result of intensive studies in view of the above-mentioned object, the present inventors have found that the acyl group is bonded to the surface and the weight loss at 200 ° C. or higher when the temperature is raised by a differential thermothermal gravimetric simultaneous measurement apparatus is 5 It has been found that titania nanoparticles having a weight percentage of at least can solve all of the above problems. Then, further research was conducted to complete the present invention. That is, the present invention includes the following configurations.
Item 1. A photocatalyst containing titania nanoparticles, wherein the titania nanoparticles have an acyl group bonded to the surface, and the weight loss at 200 ° C. or more when the temperature is raised to 600 ° C. by a differential thermogravimetric simultaneous measurement device The photocatalyst is 5% by weight or more.
Item 2. The acyl group is bonded to a titanium atom with a group represented by —OCOR (wherein R represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a hydroxyalkyl group having 1 to 2 carbon atoms). Item 2. The photocatalyst according to Item 1.
Item 3. Item 2. The photocatalyst according to Item 1, wherein the acyl group is an acyl group derived from at least one organic acid selected from the group consisting of a molar carboxylic acid having 1 to 4 carbon atoms and a hydroxycarboxylic acid having 2 to 3 carbon atoms.
Item 4. Item 4. The photocatalyst according to Item 3, wherein the organic acid is acetic acid.
Item 5. Item 5. The photocatalyst according to any one of Items 1 to 4, wherein the titania nanoparticles have an average particle diameter of 1 to 5 nm.
Item 6. Item 6. The photocatalyst according to any one of Items 1 to 5, wherein the titania nanoparticles have a specific surface area of 150 to 500 m 2 / g.
Item 7. Item 7. The photocatalyst according to any one of Items 1 to 6, wherein the titania nanoparticles do not contain a crystal form other than the anatase type.
Item 8. The method for producing a photocatalyst according to any one of Items 1 to 7,
(A) A step of mixing a substance containing titanium, an organic acid and water to obtain a dispersion, and (B) a step of heating the dispersion obtained in the step (A) at a temperature higher than 80 ° C. for 1 hour or more. And comprising
In the step (A), the mixing ratio of the substance containing titanium and the organic acid is such that the acyl group in the organic acid is 1.5 mol or more with respect to 1 mol of titanium in the substance containing titanium. Method.
Item 9. Item 9. The method according to Item 8, wherein the heating condition in the step (B) is 82 ° C or more and 1.5 hours or more.
Item 10. Item 10. The production method according to Item 8 or 9, wherein the substance containing titanium is titanium alkoxide, titanium hydroxide, or titanium halide.
Item 11. Item 11. The production method according to any one of Items 8 to 10, wherein the concentrations of the N, Cl and S elements in the dispersion prepared in the step (A) are each 0.01 mol / L or less.
Item 12. Item 12. The production method according to any one of Items 8 to 11, wherein the concentration of the inorganic acid in the dispersion produced in the step (A) is 0.01 mol / L or less.
Item 13. Item 13. The production method according to any one of Items 8 to 12, wherein the pH of the dispersion prepared in the step (B) is 2 or more and less than 6.
Item 14. Item 8. A photocatalyst dispersion liquid comprising 50% by mass or more of water and the photocatalyst according to any one of Items 1 to 7.
Item 15. Item 15. The photocatalyst dispersion according to Item 14, which does not contain an organic dispersant separately from the organic acid.
本発明によれば、大きいチタニア粒子でも小さいチタニア粒子でも達成できなかった塗布性、光触媒性及び透明性を備えたチタニア微粒子を得ることができる。 According to the present invention, it is possible to obtain titania fine particles having coating properties, photocatalytic properties, and transparency that could not be achieved with either large titania particles or small titania particles.
本明細書において、「含有」は、「含む（comprise）」、「実質的にのみからなる（consist essentially of）」、及び「のみからなる（consist of）」のいずれも包含する概念である。本明細書において、数値範囲をA〜Bで表記する場合、A以上B以下を示す。 In the present specification, “containing” is a concept including any of “comprise”, “consist essentially of”, and “consist of”. In the present specification, when the numerical range is represented by A to B, A to B is shown.
本明細書において、「酸化チタン」又は「チタニア」とは、二酸化チタン（TiO2）のみを指すものではなく、三酸化二チタン（Ti2O3）；一酸化チタン（TiO）；Ti4O7、Ti5O9等に代表される二酸化チタンから酸素欠損した組成のもの等も含む。また、末端OH基に代表されるように一部酸化チタンの合成に起因するTi-O-Ti以外の基を含んでいてもよい。さらに、末端OH基に有機酸等が結合したものも含まれる。 In the present specification, “titanium oxide” or “titania” does not only refer to titanium dioxide (TiO 2 ) but also titanium dioxide (Ti 2 O 3 ); titanium monoxide (TiO); Ti 4 O 7 and those having a composition deficient in oxygen from titanium dioxide represented by Ti 5 O 9 and the like. In addition, as represented by the terminal OH group, a group other than Ti—O—Ti resulting from the synthesis of titanium oxide may be included. Furthermore, those in which an organic acid or the like is bonded to the terminal OH group are also included.
１．光触媒
本発明の光触媒は、表面にアシル基が結合しており、且つ、示差熱熱重量同時測定装置によって600℃まで昇温させた場合の200℃以上における重量減少が5重量%以上であるチタニアナノ粒子を含有する。
1. Photocatalyst The photocatalyst of the present invention has an acyl group bonded to the surface, and the titania nanoparticle has a weight loss of 5% by weight or more at 200 ° C. or higher when the temperature is raised to 600 ° C. by a differential thermogravimetric simultaneous measurement apparatus. Contains particles.
通常、水、無機酸、遊離した有機酸等は200℃以下でほとんど揮発する。一方、本発明のチタニアナノ粒子は、表面にアシル基が結合していることから、200〜600℃の範囲で徐々に脱離する。例えばアセチル基の場合は、約260℃をピークとして200〜600℃の範囲で徐々に脱離する。このように、本発明のチタニアナノ粒子は、表面にアシル基が結合していることから、乾燥又は焼成時にチタニアナノ粒子同士の凝集を抑制できるためクラック、剥がれ等が起こりにくく塗布性及び透明性に特に優れるとともに、クラック、剥がれ等を抑制することができる結果光触媒性にも優れる。なお、通常は、アシル基を有していると光触媒性は低下するのが技術常識であるが、本発明では上記のとおりクラック、剥がれ等の抑制効果が特に優れているためアシル基を有しているにもかかわらず光触媒性も向上させることができる。 Usually, water, inorganic acids, liberated organic acids, etc. are almost volatile at 200 ° C or lower. On the other hand, since the titania nanoparticle of the present invention has an acyl group bonded to its surface, it gradually desorbs in the range of 200 to 600 ° C. For example, in the case of an acetyl group, it gradually desorbs in the range of 200 to 600 ° C. with a peak at about 260 ° C. As described above, since the titania nanoparticles of the present invention have an acyl group bonded to the surface, the aggregation of the titania nanoparticles can be suppressed at the time of drying or firing, so that cracking, peeling and the like are unlikely to occur, and the coating property and transparency are particularly good. In addition to being excellent, it is also excellent in photocatalytic properties as a result of being able to suppress cracks, peeling and the like. In general, it is common technical knowledge that the photocatalytic property is lowered when an acyl group is present, but the present invention has an acyl group because of its particularly excellent effect of suppressing cracks and peeling as described above. Despite this, the photocatalytic property can also be improved.
また、上記チタニアナノ粒子は、表面にアシル基が大量に結合していることが好ましい。表面にアシル基が存在している場合は、上記のとおり200〜600℃の範囲で徐々に離脱することから、示差熱熱重量同時測定装置（TG-DTA）によって昇温させた場合に200℃以上での重量原料が大きい。このため、示差熱熱重量同時測定装置（TG-DTA）によって600℃まで昇温させた場合の200℃以上における重量減少が5重量%以上、好ましくは7〜20重量%である。この際、示差熱熱重量同時測定装置（TG-DTA）の詳細な条件は、雰囲気：空気、昇温速度：3℃／分である。 The titania nanoparticles preferably have a large amount of acyl groups bonded to the surface. If an acyl group is present on the surface, it gradually leaves in the range of 200 to 600 ° C as described above, so when the temperature is raised by a differential thermothermal gravimetric simultaneous measurement device (TG-DTA), the temperature is 200 ° C. The weight raw material in the above is large. For this reason, the weight loss at 200 ° C. or higher when the temperature is raised to 600 ° C. by the differential thermothermal gravimetric simultaneous measurement apparatus (TG-DTA) is 5 wt% or more, preferably 7 to 20 wt%. At this time, the detailed conditions of the differential thermothermal gravimetric simultaneous measurement apparatus (TG-DTA) are: atmosphere: air, temperature rising rate: 3 ° C./min.
上記チタニアナノ粒子は、上記のとおり表面にアシル基が結合しているものであるが、このアシル基は、-OCOR（式中、Rは水素原子、炭素数1〜3のアルキル基、又は炭素数1〜2のヒドロキシアルキル基を示す）で表される基でチタン原子と結合していることが好ましい。言い換えれば、このアシル基は、炭素数1〜4のモルカルボン酸、炭素数2〜3のヒドロキシカルボン酸等の有機酸由来のアシル基であることが好ましい。 The titania nanoparticles have an acyl group bonded to the surface as described above, and this acyl group is —OCOR (wherein R is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a carbon number) It is preferably bonded to a titanium atom by a group represented by 1 to 2). In other words, this acyl group is preferably an acyl group derived from an organic acid such as a C1-C4 molar carboxylic acid or a C2-C3 hydroxycarboxylic acid.
上記Rにおいてアルキル基としては、メチル基、エチル基、n-プロピル基等が挙げられ、ヒドロキシアルキル基としては、ヒドロキシメチル基、1-ヒドロキシエチル基、2-ヒドロキシエチル基等が挙げられる。つまり、モノカルボン酸としては、ギ酸、酢酸、プロピオン酸、酪酸等が挙げられ、ヒドロキシカルボン酸としては、グリコール酸、乳酸等が挙げられる。 In R, examples of the alkyl group include a methyl group, an ethyl group, and an n-propyl group, and examples of the hydroxyalkyl group include a hydroxymethyl group, a 1-hydroxyethyl group, and a 2-hydroxyethyl group. That is, examples of the monocarboxylic acid include formic acid, acetic acid, propionic acid, and butyric acid, and examples of the hydroxycarboxylic acid include glycolic acid and lactic acid.
なお、揮発性、有害性及び分解性の観点から、Rとしては水素原子又はメチル基、ヒドロキシメチル基、1-ヒドロキシエチル基、2-ヒドロキシエチル基等が好ましく、水溶性及び臭気の観点からメチル基が好ましい。つまり、揮発性、有害性及び分解性の観点から、モノカルボン酸としてはギ酸、酢酸等が好ましく、ヒドロキシカルボン酸としてはグリコール酸、乳酸等が好ましい。また、水溶性及び臭気の観点から酢酸が特に好ましい。これらの有機酸は単独で用いることもでき、2種以上を組合せて用いることもできる。 From the viewpoints of volatility, toxicity and decomposability, R is preferably a hydrogen atom or a methyl group, a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, and the like. From the viewpoint of water solubility and odor, methyl is preferred. Groups are preferred. That is, from the viewpoints of volatility, toxicity and degradability, the monocarboxylic acid is preferably formic acid, acetic acid and the like, and the hydroxycarboxylic acid is preferably glycolic acid, lactic acid and the like. Acetic acid is particularly preferred from the viewpoint of water solubility and odor. These organic acids can be used alone or in combination of two or more.
上記チタニアナノ粒子の平均粒子径は、1〜5nmが好ましく、2〜4nmがより好ましい。チタニアナノ粒子の平均粒子径をこの範囲とすることにより、光触媒性が高く、且つ透明性の高い膜が形成できる。また、通常平均粒子径が小さい場合、加熱時の収縮が大きいため、クラックや基板からの剥離が起こりやすいが、本発明のチタニアナノ粒子は平均粒子径が小さいにも関わらず塗布性に優れる材料である。本発明のチタニアナノ粒子の平均粒子径は、電子顕微鏡（TEM）観察により測定する。 The average particle diameter of the titania nanoparticles is preferably 1 to 5 nm, and more preferably 2 to 4 nm. By setting the average particle diameter of the titania nanoparticles within this range, a film having high photocatalytic properties and high transparency can be formed. In addition, when the average particle size is usually small, since the shrinkage during heating is large, cracks and peeling from the substrate are likely to occur, but the titania nanoparticle of the present invention is a material with excellent coatability despite the small average particle size. is there. The average particle diameter of the titania nanoparticles of the present invention is measured by observation with an electron microscope (TEM).
上記チタニアナノ粒子の比表面積は、150〜500m2/gが好ましく、200〜400m2/gがより好ましい。チタニアナノ粒子の比表面積をこの範囲とすることにより、光触媒性が高くできる。上記チタニアナノ粒子の比表面積はBET法により測定する。 Specific surface area of the titania particles is preferably 150~500m 2 / g, 200~400m 2 / g is more preferable. By setting the specific surface area of the titania nanoparticles within this range, the photocatalytic property can be increased. The specific surface area of the titania nanoparticles is measured by the BET method.
また、上記チタニアナノ粒子は、N、Cl及びS元素の濃度をいずれも0〜5000ppm、特に0〜1000ppmとすることができる。チタニアナノ粒子のN、Cl及びS元素の濃度をこの範囲とすることにより、基材の腐食などを抑えることができる。なお、この条件は、TiCl4、TiOSO4等の酸性チタニア前駆体由来の不純物が存在しないか、又はごく少量であることを意味している。上記チタニアナノ粒子のN、Cl及びS元素の濃度はWDX（蛍光X線）により測定する。 In addition, the titania nanoparticles may have N, Cl and S element concentrations of 0 to 5000 ppm, particularly 0 to 1000 ppm. By setting the concentrations of the N, Cl and S elements in the titania nanoparticles within this range, corrosion of the substrate can be suppressed. This condition means that impurities derived from acidic titania precursors such as TiCl 4 and TiOSO 4 do not exist or are in a very small amount. The concentrations of N, Cl and S elements in the titania nanoparticles are measured by WDX (fluorescent X-ray).
さらに、上記チタニアナノ粒子の結晶形は、アナターゼ型が好ましい。アナターゼ型を採用することにより、光触媒性を特に向上させることができる。また、同様の理由から、アナターゼ型以外の結晶形は存在せず、アナターゼ型100%であることが好ましい。 Furthermore, the crystal form of the titania nanoparticles is preferably an anatase type. By adopting the anatase type, the photocatalytic property can be particularly improved. For the same reason, there is no crystal form other than the anatase type, and the anatase type is preferably 100%.
このようなチタニアナノ粒子は、平均粒子径及び比表面積を調整することができ、また、分散性に優れるため透明性及び塗布性に優れるものである。また、上記チタニアナノ粒子は、光触媒性にも優れている。このため、上記チタニアナノ粒子は、光触媒として有用である。 Such titania nanoparticles can adjust an average particle diameter and a specific surface area, and are excellent in dispersibility, and thus have excellent transparency and coating properties. The titania nanoparticles are also excellent in photocatalytic properties. Therefore, the titania nanoparticles are useful as a photocatalyst.
２．光触媒の製造方法
本発明の光触媒は、
（A）チタンを含む物質、有機酸及び水を混合して分散液を得る工程、及び
（B）前記工程（A）で得られた分散液を80℃より高い温度で1時間以上加熱する工程
を備え、且つ、
前記工程（A）において、前記チタンを含む物質と前記有機酸との混合比率は、前記チタンを含む物質中のチタン1モルに対して前記有機酸中のアシル基が1.5モル以上である方法により得られる。
2. Photocatalyst production method The photocatalyst of the present invention comprises:
(A) A step of mixing a substance containing titanium, an organic acid and water to obtain a dispersion, and (B) a step of heating the dispersion obtained in the step (A) at a temperature higher than 80 ° C. for 1 hour or more. And comprising
In the step (A), the mixing ratio of the substance containing titanium and the organic acid is determined by a method in which the acyl group in the organic acid is 1.5 mol or more with respect to 1 mol of titanium in the substance containing titanium. can get.
（２−１）工程（A）
工程（A）では、特定量のチタンを含む物質、特定量の有機酸及び水を混合して分散液を得る。
(2-1) Step (A)
In the step (A), a substance containing a specific amount of titanium, a specific amount of organic acid, and water are mixed to obtain a dispersion.
使用するチタンを含む物質としては、加熱により酸化チタンとなる物質であれば特に制限はない。つまり、チタンを含む物質としては、酸化チタン及び／又は酸化チタン前駆体が好ましく、具体的には、酸化チタン；水酸化チタン；チタンアルコキシド；三塩化チタン、四塩化チタン等のハロゲン化チタン（特に塩基で中和したもの）；金属チタン等が挙げられる。これらのチタンを含む物質は単独で用いることもでき、2種以上を組合せて用いることもできる。これらのなかでも、得られるチタニアの分散性、塗布性及び光触媒性の観点から、チタンアルコキシド、水酸化チタン又はハロゲン化チタン（特に塩基で中和したもの）が好ましく、特に純度、分散性、塗布性及び光触媒性の観点からチタンアルコキシドがより好ましい。 The substance containing titanium to be used is not particularly limited as long as it is a substance that becomes titanium oxide by heating. That is, as the substance containing titanium, titanium oxide and / or a titanium oxide precursor are preferable. Specifically, titanium oxide; titanium hydroxide; titanium alkoxide; titanium halide such as titanium trichloride and titanium tetrachloride (especially Neutralized with a base); metal titanium and the like. These substances containing titanium can be used alone or in combination of two or more. Of these, titanium alkoxide, titanium hydroxide or titanium halide (especially those neutralized with a base) are preferred from the viewpoint of dispersibility, coating properties and photocatalytic properties of the titania obtained, and particularly purity, dispersibility, coating properties. Titanium alkoxide is more preferable from the viewpoints of photocatalytic properties and photocatalytic properties.
チタンアルコキシドとしては、チタンテトライソプロポキシド、チタンテトラn-ブトキシド、チタンテトラn-プロポキシド、チタンテトラエトキシド等が挙げられ、コスト、副生成物の水溶性、塗布性及び光触媒性の観点から、チタンテトライソプロポキシドが好ましい。 Examples of titanium alkoxide include titanium tetraisopropoxide, titanium tetra n-butoxide, titanium tetra n-propoxide, titanium tetraethoxide, and the like, from the viewpoint of cost, water solubility of by-products, coating properties, and photocatalytic properties. Titanium tetraisopropoxide is preferred.
なお、チタンアルコキシドと有機酸との組合せによっては、得られるチタニアを触媒として水に溶けにくいエステル化合物が遊離することがあるが、チタニア自身には問題はない（例えば、チタンテトラn-ブトキシドと酢酸の組合せにおいて、混合し加熱した段階で酢酸ブチルが生じ遊離する）が、均一な分散液を得る観点からは、水溶性に優れる有機酸アルコキシドが得られる有機酸とチタンアルコキシドとの組合せを採用することが好ましい。 Depending on the combination of titanium alkoxide and organic acid, an ester compound that is hardly soluble in water may be liberated using the obtained titania as a catalyst, but titania itself has no problem (for example, titanium tetra-n-butoxide and acetic acid). However, from the viewpoint of obtaining a uniform dispersion, a combination of an organic acid and a titanium alkoxide is used from which a water-soluble organic acid alkoxide can be obtained. It is preferable.
ハロゲン化チタン（四塩化チタン、三塩化チタン等）については、不純物（ハロゲン）、量産時の反応器の腐食、結晶性制御、塗布性及び光触媒性の観点から、塩基で中和し、沈殿物の洗浄を行ってから用いることが好ましい。その場合、得られるチタニアの分散性の観点から、乾燥を行わずに用いることが好ましい。 Titanium halides (titanium tetrachloride, titanium trichloride, etc.) are neutralized with a base from the viewpoint of impurities (halogen), corrosion of the reactor during mass production, crystallinity control, coating properties and photocatalytic properties, and precipitates. It is preferable to use after washing. In that case, it is preferable to use without performing drying from a dispersible viewpoint of the titania obtained.
なお、酸化チタン、金属チタン等の固体を用いる場合は、平均粒子径は100nm以下が好ましく、50nm以下がより好ましい。下限値は特に設定されないが、通常1nm程度である。なお、粒径が大きい場合は遊星ボールミル、ペイントシェーカー等を用いて乾式又は湿式で粉砕して用いることもできる。酸化チタン、金属チタン等の固体の平均粒子径は、電子顕微鏡（SEM又はTEM）観察等により測定する。 When a solid such as titanium oxide or metallic titanium is used, the average particle size is preferably 100 nm or less, and more preferably 50 nm or less. The lower limit is not particularly set, but is usually about 1 nm. When the particle size is large, it can be used after dry or wet pulverization using a planetary ball mill, paint shaker or the like. The average particle diameter of solids such as titanium oxide and titanium metal is measured by observation with an electron microscope (SEM or TEM).
分散液中のチタンを含む物質の濃度は、生産性、反応液の粘度、塗布性及び光触媒性の観点から、0.01〜5mol/Lが好ましく、0.05〜3mol/Lがより好ましい。 The concentration of the substance containing titanium in the dispersion is preferably 0.01 to 5 mol / L, more preferably 0.05 to 3 mol / L, from the viewpoints of productivity, viscosity of the reaction solution, coating property, and photocatalytic property.
反応に使用する酸は、有機酸であり、揮発性のある酸が好ましいことから化学式CnH2n+1COOH（n= 0〜3）で示されるモノカルボン酸、炭素数2〜3のヒドロキシカルボン酸等が挙げられる。 The acid used in the reaction is an organic acid, and a volatile acid is preferable. Therefore, a monocarboxylic acid represented by the chemical formula C n H 2n + 1 COOH (n = 0 to 3), hydroxy having 2 to 3 carbon atoms A carboxylic acid etc. are mentioned.
揮発性、有害性及び分解性の観点から、モノカルボン酸としてはn= 0のギ酸及びn= 1の酢酸が好ましく、ヒドロキシカルボン酸としてはグリコール酸、乳酸等が好ましく、水溶性及び臭気の観点から酢酸が特に好ましい。これらの有機酸は単独で用いることもでき、2種以上を組合せて用いることもできる。 From the viewpoints of volatility, harmfulness and degradability, monocarboxylic acid is preferably n = 0 formic acid and n = 1 acetic acid, and hydroxycarboxylic acid is preferably glycolic acid, lactic acid, etc., and has water solubility and odor. To acetic acid is particularly preferred. These organic acids can be used alone or in combination of two or more.
有機酸の使用量は、分散性、塗布性、光触媒性及びコストの観点から、チタンを含む物質中のチタン1モルに対して、COOH基を1.5モル以上、好ましくは2モル含むように調整することが好ましい。有機酸を多く用いるほど経時安定性、塗布性等が向上する。なお、上限値は特に制限されないが、チタンを含む物質中のチタン1モルに対して通常10モルである。 The amount of organic acid used is adjusted so that it contains 1.5 moles or more, preferably 2 moles of COOH groups with respect to 1 mole of titanium in the substance containing titanium, from the viewpoints of dispersibility, coatability, photocatalytic properties and cost. It is preferable. As more organic acid is used, stability over time, coating properties, and the like are improved. The upper limit is not particularly limited, but is usually 10 moles with respect to 1 mole of titanium in the substance containing titanium.
分散液中の有機酸の濃度は、分散性、塗布性、光触媒性及びコストの観点から、0.02〜10mol/Lが好ましく、0.1〜7mol/Lがより好ましい。 The concentration of the organic acid in the dispersion is preferably from 0.02 to 10 mol / L, more preferably from 0.1 to 7 mol / L, from the viewpoints of dispersibility, coatability, photocatalytic property, and cost.
反応溶媒としては、水等の水性溶媒を主成分（具体的には、例えば50質量%以上）として用いることが好ましいが、反応時にアルコール又はエステルを含んでいてもよい。 As the reaction solvent, an aqueous solvent such as water is preferably used as a main component (specifically, for example, 50% by mass or more), but may contain alcohol or ester during the reaction.
例えばチタンテトライソプロポキシドを原料として用いた場合、有機酸との反応によりイソプロパノールが生じる。また、加熱により有機酸のイソプロピルエステルが生じることもある。つまり、工程（A）により得られる分散液中には、アルコール又はエステルを投入してもよいし、系中で発生していてもよい。このアルコール又はエステルについては、100℃以下の開放系における加熱により除去してもよいし、減圧により除去してもよいし，反応液中に残留していてもよい。 For example, when titanium tetraisopropoxide is used as a raw material, isopropanol is produced by reaction with an organic acid. Moreover, the isopropyl ester of organic acid may be produced by heating. That is, alcohol or ester may be added to the dispersion obtained by the step (A) or may be generated in the system. The alcohol or ester may be removed by heating in an open system at 100 ° C. or lower, may be removed by reduced pressure, or may remain in the reaction solution.
なお、分散液中にアルコールが含まれる場合には、得られるチタニアナノ粒子の平均粒子径が小さくなる傾向にあり、平均粒子径を制御するために、意図的にアルコールを添加してもよい。 In addition, when alcohol is contained in the dispersion, the average particle diameter of the obtained titania nanoparticles tends to be small, and alcohol may be intentionally added to control the average particle diameter.
本発明においては、通常チタニアナノ粒子の水熱合成反応に用いることが多い硝酸、塩酸、硫酸等の無機酸（特に無機強酸）は、得られるチタニアナノ粒子の結晶形がアナターゼ型の他にブルッカイト型も混在するだけでなく、得られる分散液の貯蔵安定性にも劣り、装置の腐食、不純物、排水等の観点からも原則用いない。ただし、原料の分散性、均一性等を高め取扱いを容易にする場合には、効果を損なわない範囲で、例えば、0.01mol/L以下の範囲で補助的に使用することもできる。この場合、分散液中のN、Cl及びS元素の濃度がいずれも0.01mol/L以下となる。 In the present invention, inorganic acids (particularly strong inorganic acids) such as nitric acid, hydrochloric acid, and sulfuric acid, which are usually used for the hydrothermal synthesis reaction of titania nanoparticles, are not limited to the anatase type, but also the brookite type. In addition to being mixed, it is inferior in storage stability of the resulting dispersion, and is not used in principle from the viewpoint of equipment corrosion, impurities, drainage, etc. However, when the dispersibility, uniformity, etc. of the raw materials are increased to facilitate handling, they can be used supplementarily within a range where the effect is not impaired, for example, within a range of 0.01 mol / L or less. In this case, the concentrations of N, Cl, and S elements in the dispersion are all 0.01 mol / L or less.
このような工程（A）で得られる分散液のpHは、装置の腐食や取扱いの安全性、及び分散性の観点から、2以上6未満が好ましく、2.1〜5がより好ましい。 The pH of the dispersion obtained in such a step (A) is preferably 2 or more and less than 6, and more preferably 2.1 to 5 from the viewpoints of corrosion of the apparatus, safety in handling, and dispersibility.
工程（A）において、分散液の作製方法は特に制限はなく、チタンを含む物質、有機酸及び水（溶媒）を同時に混合してもよいし、逐次混合してもよい。特に、凝集して大きな塊を形成しにくく攪拌を継続できる観点から、有機酸及び水（溶媒）を混合した後に、攪拌しながらチタンを含む物質を投入することが好ましい。 In the step (A), the method for preparing the dispersion is not particularly limited, and the substance containing titanium, the organic acid, and water (solvent) may be mixed simultaneously or sequentially. In particular, from the viewpoint of preventing agglomeration and forming a large lump so that stirring can be continued, it is preferable to add a substance containing titanium while stirring after mixing the organic acid and water (solvent).
（２−２）工程（B）
工程（B）においては、工程（A）で得られた分散液を80℃より高い温度で1時間以上加熱する。
(2-2) Step (B)
In the step (B), the dispersion obtained in the step (A) is heated at a temperature higher than 80 ° C. for 1 hour or longer.
工程（B）は、常圧下に行ってもよいし、密閉容器内で加圧下に行ってもよい。チタニアナノ粒子の平均粒子径を小さくする観点から、常圧下に行うことが好ましく、具体的には0.09〜0.11MPaが好ましい。なお、加圧下に行う場合は、光触媒性が高く、且つ透明性の高い膜が形成できる観点からは、0.2MPa以下（0.11〜0.2MPa）において短時間（例えば5〜30分程度）の反応を行うことが好ましい。 Step (B) may be performed under normal pressure, or may be performed under pressure in a sealed container. From the viewpoint of reducing the average particle size of the titania nanoparticles, it is preferably carried out under normal pressure, specifically 0.09 to 0.11 MPa. In addition, when performed under pressure, from the viewpoint of forming a highly transparent film having high photocatalytic properties, a reaction for a short time (for example, about 5 to 30 minutes) is performed at 0.2 MPa or less (0.11 to 0.2 MPa). Preferably it is done.
加熱の際には、チタンを含む物質と有機酸と水を十分に反応する観点から、撹拌することが好ましい。攪拌の方法は特に制限はなく、常法に従うことができる。また、攪拌時間は、チタンを含む物質と有機酸と水を十分に反応する観点から、1時間以上が好ましく、1.5時間以上がより好ましい。攪拌時間の上限値は特に制限されないが、通常240時間である。 In heating, it is preferable to stir from the viewpoint of sufficiently reacting the substance containing titanium, the organic acid, and water. There is no restriction | limiting in particular in the method of stirring, It can follow a conventional method. The stirring time is preferably 1 hour or longer, more preferably 1.5 hours or longer, from the viewpoint of sufficiently reacting the substance containing titanium, the organic acid and water. The upper limit of the stirring time is not particularly limited, but is usually 240 hours.
加熱温度は、80℃より高い温度、好ましくは82℃以上である。加熱温度が80℃以下では、クラックが発生しやすく、塗布性に劣りすぐに脱落することから塗膜を形成することが困難となる。なお、加熱温度の上限値は特に制限はないが、常圧で反応する場合は通常120℃である。 The heating temperature is higher than 80 ° C, preferably 82 ° C or higher. When the heating temperature is 80 ° C. or lower, cracks are likely to occur, the coating property is poor, and the coating film falls off immediately, making it difficult to form a coating film. The upper limit of the heating temperature is not particularly limited, but is usually 120 ° C. when reacting at normal pressure.
このような工程（B）で得られる分散液のpHは、装置の腐食や取扱いの安全性、及び分散性の観点から、2以上6未満が好ましく、2.1〜5がより好ましい。 The pH of the dispersion obtained in the step (B) is preferably 2 or more and less than 6 and more preferably 2.1 to 5 from the viewpoint of corrosion of the apparatus, safety of handling, and dispersibility.
この後、常法により、チタニアナノ粒子を沈殿及び遠心分離すること等により、本発明の光触媒を回収することができる。つまり、大量のアシル基が表面に結合したチタニアナノ粒子を含有する光触媒を得ることができる。 Thereafter, the photocatalyst of the present invention can be recovered by precipitation and centrifugation of titania nanoparticles by a conventional method. That is, a photocatalyst containing titania nanoparticles having a large amount of acyl groups bonded to the surface can be obtained.
３．光触媒分散液
本発明の光触媒分散液は、上記工程（A）〜（B）を経た反応液を用い、超音波分散等の分散工程を加えることにより、さらに均一な分散液を作製できる。この時、従来のチタニア分散液においては分散剤を使用しなければ均一な分散液を得ることができなかったことから、本発明においても、分散剤を加えてもよいが、分散剤を加えなくても通常のチタニアナノ粒子より遥かに分散性のよい分散液が得られる。分散性がよい結果、コーティングの耐クラック性にも優れる。また、分散剤を加えなくてもよい結果、緻密なチタニアのコーティングが可能になる。
3. Photocatalyst dispersion liquid The photocatalyst dispersion liquid of the present invention can produce a more uniform dispersion liquid by adding a dispersion process such as ultrasonic dispersion using the reaction liquid that has undergone the above steps (A) to (B). At this time, in the conventional titania dispersion, since a uniform dispersion could not be obtained unless a dispersant was used, in the present invention, a dispersant may be added, but a dispersant is not added. However, a dispersion having far better dispersibility than ordinary titania nanoparticles can be obtained. As a result of good dispersibility, the coating has excellent crack resistance. Further, as a result of not having to add a dispersant, a dense titania coating is possible.
この際、本発明の光触媒分散液においては、本発明の光触媒分散液の総量を100質量%として、溶媒である水の含有量をコーティングの容易さ、及びコーティングの膜性の観点から、50質量%以上、特に60質量%以上とすることが好ましい。 At this time, in the photocatalyst dispersion of the present invention, the total amount of the photocatalyst dispersion of the present invention is 100% by mass, and the content of water as a solvent is 50 mass from the viewpoint of ease of coating and coating film properties. % Or more, preferably 60% by mass or more.
また、本発明の光触媒を反応液から取り出し、溶媒を変更することも可能である。反応液から遠心分離やろ過膜等により水分を除去し、有機溶媒に置換してもよい。その際は本発明の光触媒を乾燥させないことが、分散性、透明性等の観点から好ましい。 It is also possible to take out the photocatalyst of the present invention from the reaction solution and change the solvent. Water may be removed from the reaction solution by centrifugation, filtration membrane or the like, and replaced with an organic solvent. In that case, it is preferable not to dry the photocatalyst of the present invention from the viewpoint of dispersibility, transparency and the like.
分散液に使用する有機溶媒としては、アルコール等が挙げられる。このアルコールとしては、メタノール、エタノール、イソプロパノール等の炭素数1〜6の脂肪族アルコールの他、α-テルピネオール等の非脂肪族アルコール；ブチルカルビトール（ジエチレングリコールモノブチルエーテル）、ヘキシレングリコール（2-メチル-2,4-ペンタンジオール）、エチレングリコール-2-エチルヘキシルエーテル、エチレングリコールモノメチルエーテル、プロピレングリコールモノメチルエーテル等のグリコール系溶媒；1,4-ブタンジオール、1,5-ペンタンジオール、1,6-ヘキサンジオール等のジオール等が挙げられる。 Examples of the organic solvent used in the dispersion include alcohol. Examples of the alcohol include aliphatic alcohols having 1 to 6 carbon atoms such as methanol, ethanol and isopropanol, and non-aliphatic alcohols such as α-terpineol; butyl carbitol (diethylene glycol monobutyl ether), hexylene glycol (2-methyl -2,4-pentanediol), glycol solvents such as ethylene glycol-2-ethylhexyl ether, ethylene glycol monomethyl ether, propylene glycol monomethyl ether; 1,4-butanediol, 1,5-pentanediol, 1,6- Examples include diols such as hexanediol.
また、OH基を有さなくても、チタニア及び他の溶媒（水、アルコール等）との親和性があればよく、ジエチレングリコールブチルメチルエーテル、トリプロピレングリコールジメチルエーテル、トリエチレングリコールジメチルエーテル、ジエチレングリコールジブチルエーテル、トリエチレングリコールブチルメチルエーテル、テトラエチレングリコールジメチルエーテル、ジエチレングリコールモノブチルエーテルアセテート、ジエチレングリコールモノエチルエーテルアセテート、ジエチレングリコールジアセテート、トリエチレングリコールジアセテート、テトラエチレングリコールジアセテート等が挙げられる。なかでも、沸点等の観点から、ジエチレングリコールモノブチルエーテルアセテート、テトラエチレングリコールジメチルエーテル等が好ましい。 Moreover, even if it does not have an OH group, it only needs to have an affinity with titania and other solvents (water, alcohol, etc.), diethylene glycol butyl methyl ether, tripropylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol dibutyl ether, Examples include triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol diacetate, triethylene glycol diacetate, and tetraethylene glycol diacetate. Of these, diethylene glycol monobutyl ether acetate, tetraethylene glycol dimethyl ether and the like are preferable from the viewpoint of boiling point and the like.
本発明の光触媒分散液は、用途に応じて粘度を調整し、例えば、スピンコート、ディップコート、スプレー等に用いる場合は低粘度、刷毛塗り、スキージ法等に用いる場合はそれより粘度を高く調整し、スクリーン印刷に用いる場合は、さらに粘度を高く調製し、流動性を抑制することが好ましい。このようにして得られる本発明の塗膜は、上記のとおり緻密なコーティングである。 The photocatalyst dispersion of the present invention adjusts the viscosity according to the application, for example, low viscosity when used for spin coating, dip coating, spraying, etc., and higher viscosity when used for brush coating, squeegee method, etc. And when using for screen printing, it is preferable to adjust viscosity further and to suppress fluidity | liquidity. The coating film of the present invention thus obtained is a dense coating as described above.
実施例に基づいて、本発明を具体的に説明するが、本発明は、これらのみに限定されるものではない。 The present invention will be specifically described based on examples, but the present invention is not limited to these examples.
［実施例1］
チタンテトライソプロポキシド142.1g（0.5mol）に酢酸120g（2mol）を加え60分撹拌し、水を538g加えた。この分散液は、チタンテトライソプロポキシドの濃度は0.625mol/L、酢酸の濃度は2.5mol/L、pHは2.2であった。半透明の沈殿が大量に発生したが、60分間撹拌した後に加熱を行ったところ70℃で沈殿がすべて溶解した。なお、この分散液において、無機酸の濃度、N、Cl及びS元素の濃度はいずれも0mol/Lである。
[Example 1]
To 142.1 g (0.5 mol) of titanium tetraisopropoxide, 120 g (2 mol) of acetic acid was added and stirred for 60 minutes, and 538 g of water was added. This dispersion had a titanium tetraisopropoxide concentration of 0.625 mol / L, an acetic acid concentration of 2.5 mol / L, and a pH of 2.2. Although a large amount of translucent precipitate was generated, heating was performed after stirring for 60 minutes, and all the precipitate was dissolved at 70 ° C. In this dispersion, the concentration of the inorganic acid and the concentrations of N, Cl and S are all 0 mol / L.
その後、常圧（0.1MPa）で85℃で3時間撹拌したところ、有機分散剤を使うことなく半透明の均一なチタニア分散液が得られた。この分散液に超音波分散を加えたところ、粘度が低減され、透明性が増した。この分散液は水の含有量が67質量%でありpHは2.3であった。この分散液をスピンコートによりガラスに塗布し、乾燥したところ、透明な塗膜が得られた。 Thereafter, the mixture was stirred at 85 ° C. for 3 hours at normal pressure (0.1 MPa), and a translucent and uniform titania dispersion was obtained without using an organic dispersant. When ultrasonic dispersion was added to this dispersion, the viscosity was reduced and the transparency was increased. This dispersion had a water content of 67% by mass and a pH of 2.3. When this dispersion was applied to glass by spin coating and dried, a transparent coating film was obtained.
この分散液を乾燥し、チタニアナノ粒子を得た。このチタニアナノ粒子について、BET比表面積を測定したところ250m2/gであった。また、TEM観察を行ったところ、平均粒子径は約3nmであった。また得られたチタニアナノ粒子について、X線回折で結晶性を解析したところ、アナターゼ型100%であった（他の結晶形は存在しなかった）。 This dispersion was dried to obtain titania nanoparticles. With respect to the titania nanoparticles, the BET specific surface area was measured and found to be 250 m 2 / g. Further, when TEM observation was performed, the average particle size was about 3 nm. Further, when the obtained titania nanoparticles were analyzed for crystallinity by X-ray diffraction, they were found to be 100% anatase (no other crystal forms existed).
この分散液を、水分計を用いて200℃で保持し重量減少がなくなるまで乾燥したチタニアナノ粒子のTG-DTAを、空気雰囲気下3℃／minの昇温条件で600℃まで昇温させて測定したところ、200℃以上での重量減少は10%であった。この200℃以上での重量減少は、有機酸である酢酸が脱離することによる重量減少に相当する。遊離した酢酸は200℃以下でほとんど揮発することから、200℃以上における重量減少が10%あることが、本発明のチタニアナノ粒子表面にアシル基である大量のアセチル基が-OCOCH3の形でチタン原子と結合していることを示唆している。 TG-DTA, a titania nanoparticle that was dried at 200 ° C using a moisture meter and dried until there was no weight loss, was measured by raising the temperature to 600 ° C under a temperature rise condition of 3 ° C / min in an air atmosphere. As a result, the weight loss at 200 ° C. or higher was 10%. This weight reduction at 200 ° C. or higher corresponds to weight reduction due to elimination of acetic acid, which is an organic acid. Since the liberated acetic acid is almost volatilized at 200 ° C or lower, there is a 10% weight loss at 200 ° C or higher, which means that a large amount of acetyl groups as acyl groups on the surface of the titania nanoparticles of the present invention is in the form of -OCOCH 3 This suggests that it is bonded to an atom.
次に、この分散液を厚さ1mmのガラスに塗布（スピンコート）した基板を120℃で乾燥し、587.6nm（d線：メチレンブルーの吸収ピークに近い波長）の透過率を紫外・可視分光測定装置（島津製作所 UV3400）により測定したところ90.9であった。メチレンブルー1mmol/Lの溶液を基板に滴下し、10分後余分な液を除去した。浸漬後の587.6nmの透過率を紫外・可視分光測定装置により測定したところ74.9%であった。その後、ブラックライトによるピーク波長352nm紫外光の照射を行ったところ、5時間で色が消失し、透過率が色素浸漬前の91.2%に回復した。 Next, a substrate coated with this dispersion on 1 mm thick glass (spin coated) is dried at 120 ° C., and the transmittance at 587.6 nm (d-line: wavelength close to the absorption peak of methylene blue) is measured by ultraviolet / visible spectroscopy. It was 90.9 as measured by a device (Shimadzu Corporation UV3400). A solution of 1 mmol / L of methylene blue was dropped on the substrate, and after 10 minutes, excess liquid was removed. The transmittance at 587.6 nm after immersion was measured by an ultraviolet / visible spectrophotometer to be 74.9%. Thereafter, irradiation with ultraviolet light having a peak wavelength of 352 nm with black light was performed, the color disappeared in 5 hours, and the transmittance recovered to 91.2% before dye immersion.
［比較例1］
チタンテトライソプロポキシド142.1g（0.5mol）に酢酸を30g（0.5mol）加え15分撹拌し、水を625g加えた。この分散液は、チタンテトライソプロポキシドの濃度は0.625mol/L、酢酸の濃度は0.625mol/L、pHは2.9であった。半透明の沈殿が大量に発生したが、65%硝酸を4ml加え、60分間撹拌しながら加熱を行ったところ50℃で沈殿がすべて溶解した。なお、この分散液において、無機酸の濃度は0.05mol/L、Nの濃度は0.05mol/L、Cl及びS元素の濃度はいずれも0mol/Lである。
[Comparative Example 1]
Acetic acid (30 g, 0.5 mol) was added to titanium tetraisopropoxide (142.1 g, 0.5 mol) and stirred for 15 minutes, and water (625 g) was added. This dispersion had a titanium tetraisopropoxide concentration of 0.625 mol / L, an acetic acid concentration of 0.625 mol / L, and a pH of 2.9. Although a large amount of translucent precipitate was generated, 4 ml of 65% nitric acid was added and heated with stirring for 60 minutes. All precipitates were dissolved at 50 ° C. In this dispersion, the concentration of the inorganic acid is 0.05 mol / L, the concentration of N is 0.05 mol / L, and the concentrations of Cl and S elements are all 0 mol / L.
その後、常圧（0.1MPa）で80℃で5時間撹拌した液に水を加え、合計800gに調製した後、超音波をかけたところ、半透明の均一なチタニア分散液が得られた。この分散液は水の含有量が62.5質量%以上でありpHは0.7であった。 Thereafter, water was added to the liquid stirred at 80 ° C. for 5 hours at normal pressure (0.1 MPa) to prepare a total of 800 g, and then subjected to ultrasonic waves. As a result, a translucent uniform titania dispersion was obtained. This dispersion had a water content of 62.5% by mass or more and a pH of 0.7.
この分散液を乾燥し、チタニアナノ粒子を得た。このチタニアナノ粒子について、BET比表面積を測定したところ280m2/gであった。また、TEM観察を行ったところ、平均粒子径は約3nmであった。また得られたチタニアナノ粒子について、X線回折で結晶性を解析したところ、ほとんどアナターゼ型であったが、ブルッカイト型も少量混在していた。この分散液をガラス基板に塗布し、乾燥したところ、実施例1と同等の比表面積と粒径であるにも関わらず、塗膜にクラックが生じ、ガラスから脱落した。 This dispersion was dried to obtain titania nanoparticles. With respect to the titania nanoparticles, the BET specific surface area was measured and found to be 280 m 2 / g. Further, when TEM observation was performed, the average particle size was about 3 nm. The obtained titania nanoparticles were analyzed for crystallinity by X-ray diffraction. As a result, they were almost anatase type, but a small amount of brookite type was also mixed. When this dispersion was applied to a glass substrate and dried, despite the specific surface area and particle size equivalent to those of Example 1, the coating film was cracked and dropped from the glass.
［比較例2］
pH0.7の硝酸水溶液650gを撹拌しながら、チタンテトライソプロポキシド142.1g（0.5mol）を加えた。この分散液は、チタンテトライソプロポキシドの濃度は0.625mol/L、pHは1.0であった。なお、この分散液において、無機酸の濃度は0.25mol/L、Cl及びS元素の濃度はいずれも0mol/Lである。
[Comparative Example 2]
While stirring 650 g of an aqueous nitric acid solution having a pH of 0.7, 142.1 g (0.5 mol) of titanium tetraisopropoxide was added. This dispersion had a titanium tetraisopropoxide concentration of 0.625 mol / L and a pH of 1.0. In this dispersion, the concentration of inorganic acid is 0.25 mol / L, and the concentrations of Cl and S elements are both 0 mol / L.
この分散液を1時間撹拌したのち、常圧（0.1MPa）で80℃に昇温して8時間保持し、半透明のチタニア分散液を合成した。最終重量は800gに調整した。この分散液は水の含有量が80質量%でありpHは1.0であった。 After stirring this dispersion for 1 hour, the temperature was raised to 80 ° C. at normal pressure (0.1 MPa) and maintained for 8 hours to synthesize a translucent titania dispersion. The final weight was adjusted to 800 g. This dispersion had a water content of 80% by mass and a pH of 1.0.
この分散液を乾燥し、チタニアナノ粒子を得た。このチタニアナノ粒子について、BET比表面積を測定したところ220m2/gであった。また、TEM観察を行ったところ、平均粒子径は約3nmであった。また得られたチタニアナノ粒子について、X線回折で結晶性を解析したところ、ほとんどアナターゼ型であったが、ブルッカイト型も少量混在していた。この分散液をガラス基板に塗布し、乾燥したところ、塗膜にクラックが生じ、ガラスから剥離及び脱落した。 This dispersion was dried to obtain titania nanoparticles. With respect to the titania nanoparticles, the BET specific surface area was measured and found to be 220 m 2 / g. Further, when TEM observation was performed, the average particle size was about 3 nm. The obtained titania nanoparticles were analyzed for crystallinity by X-ray diffraction. As a result, they were almost anatase type, but a small amount of brookite type was also mixed. When this dispersion was applied to a glass substrate and dried, the coating film was cracked and peeled off and dropped from the glass.
また、原料のチタニア分散液を7日後に観察したところ、沈殿が発生し、ゲル化が進行して高粘度化しており貯蔵安定性にも難があった。 Further, when the titania dispersion as a raw material was observed after 7 days, precipitation occurred, gelation progressed to increase the viscosity, and storage stability was also difficult.
［比較例3］
チタニアナノ粒子ST-01（石原産業（株）製、比表面積300m2/g、比表面積から計算した平均粒子径5nm）10gに酢酸30gと水160gを加え、超音波分散を行ったが、均一な溶液が得られなかった。
[Comparative Example 3]
30 g of acetic acid and 160 g of water were added to 10 g of titania nano particles ST-01 (Ishihara Sangyo Co., Ltd., specific surface area 300 m 2 / g, average particle diameter 5 nm calculated from the specific surface area), and ultrasonic dispersion was performed. No solution was obtained.
この分散液をガラス基板上に塗布したが、チタニア膜が完全に不透明であった。 This dispersion was applied on a glass substrate, but the titania film was completely opaque.
［比較例4］
チタニアナノ粒子ST-01（石原産業（株）製、比表面積300m2/g、比表面積から計算した平均粒子径5nm）10gに酢酸30gと水160gを加え，80℃で3時間撹拌した後、超音波分散を行ったが、均一な溶液が得られなかった。
[Comparative Example 4]
30 g of acetic acid and 160 g of water were added to 10 g of titania nano particles ST-01 (Ishihara Sangyo Co., Ltd., specific surface area 300 m 2 / g, average particle diameter calculated from specific surface area 5 nm), and stirred at 80 ° C. for 3 hours. Although sonic dispersion was performed, a uniform solution was not obtained.
この分散液をガラス基板上に塗布したが、チタニア膜が完全に不透明であった。 This dispersion was applied on a glass substrate, but the titania film was completely opaque.
［比較例5］
チタニアナノ粒子=25（日本アエロジル（株）製、比表面積50m2/g、比表面積から計算した平均粒子径5nm）10gに酢酸30gと水160gを加え、超音波分散を行ったところ、均一な溶液が得られなかった。
[Comparative Example 5]
Titania nanoparticles = 25 (manufactured by Nippon Aerosil Co., Ltd., specific surface area 50 m 2 / g, average particle diameter calculated from specific surface area 5 nm) 10 g of acetic acid 30 g and 160 g of water were added, and ultrasonic dispersion was performed. Was not obtained.
次に、この分散液を厚さ1mmのガラスに塗布（スピンコート）した基板を120℃で乾燥し、587.6nm（d線：メチレンブルーの吸収ピークに近い波長）の透過率を紫外・可視分光測定装置（島津製作所 UV3400）により測定したところ91.3%であった。この分散液を厚さ1mmのガラスにスピンコートしたところ、白濁しているが目視では均一で半透明の塗膜が得られた。次に、この塗膜を120℃で乾燥し、メチレンブルー1mmol/Lの溶液を基板に滴下し、10分後余分な液を除去した。浸漬後の可視光の透過率を紫外・可視分光測定装置により測定したところ82.7%であり、実施例１と比較して色素の吸着量が少なかった。その後、ブラックライトによるピーク波長352nmの紫外光の照射を行ったところ、5時間後の587.6nmの透過率は87.0%、20時間後の587.6nmの透過率は91.1%と、色が消失するのに20時間を要したことから光触媒性に劣ることが理解できる。 Next, a substrate coated with this dispersion on 1 mm thick glass (spin-coated) is dried at 120 ° C, and the transmittance at 587.6 nm (d-line: wavelength close to the absorption peak of methylene blue) is measured by ultraviolet and visible spectroscopy. It was 91.3% when measured by an apparatus (Shimadzu Corporation UV3400). When this dispersion was spin-coated on glass having a thickness of 1 mm, it was cloudy but a uniform and translucent coating film was obtained visually. Next, this coating film was dried at 120 ° C., a solution of 1 mmol / L of methylene blue was dropped on the substrate, and after 10 minutes, the excess liquid was removed. When the visible light transmittance after immersion was measured with an ultraviolet / visible spectroscopic measurement device, it was 82.7%, and the amount of dye adsorbed was small compared to Example 1. After that, when ultraviolet light with a peak wavelength of 352 nm was irradiated with black light, the transmittance of 587.6 nm after 5 hours was 87.0%, the transmittance of 587.6 nm after 20 hours was 91.1%, and the color disappeared. Therefore, it can be understood that the photocatalytic property is poor.
Claims (15)
（A）チタンを含む物質、有機酸及び水を混合して分散液を得る工程、及び
（B）前記工程（A）で得られた分散液を80℃より高い温度で1時間以上加熱する工程
を備え、且つ、
前記工程（A）において、前記チタンを含む物質と前記有機酸との混合比率は、前記チタンを含む物質中のチタン1モルに対して前記有機酸中のアシル基が1.5モル以上である、製造方法。 A method for producing a photocatalyst according to any one of claims 1 to 7,
(A) A step of mixing a substance containing titanium, an organic acid and water to obtain a dispersion, and (B) a step of heating the dispersion obtained in the step (A) at a temperature higher than 80 ° C. for 1 hour or more. And comprising
In the step (A), the mixing ratio of the substance containing titanium and the organic acid is such that the acyl group in the organic acid is 1.5 mol or more with respect to 1 mol of titanium in the substance containing titanium. Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018064190A JP7206056B2 (en) | 2018-03-29 | 2018-03-29 | photocatalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018064190A JP7206056B2 (en) | 2018-03-29 | 2018-03-29 | photocatalyst |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2019171319A true JP2019171319A (en) | 2019-10-10 |
| JP7206056B2 JP7206056B2 (en) | 2023-01-17 |
Family
ID=68166205
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2018064190A Active JP7206056B2 (en) | 2018-03-29 | 2018-03-29 | photocatalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP7206056B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2021154233A (en) * | 2020-03-27 | 2021-10-07 | 大阪瓦斯株式会社 | Metal nanoparticle carrying titania nanoparticle and photocatalyst using the same |
| JP7539780B2 (en) | 2020-03-27 | 2024-08-26 | 大阪瓦斯株式会社 | Titania nanoparticles carrying metal nanoparticles and photocatalysts using the same |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001262007A (en) * | 2000-03-17 | 2001-09-26 | Mitsubishi Gas Chem Co Inc | Titania coating liquid and its production method, and titania film and its formation method |
| JP2002320917A (en) * | 2001-04-27 | 2002-11-05 | Toto Ltd | Production method for photocatalytic coating film and photocatalytic material |
| JP2004018477A (en) * | 2002-06-18 | 2004-01-22 | Idemitsu Kosan Co Ltd | Water-soluble titanium compound and method for producing the same |
| JP2004507421A (en) * | 2000-07-17 | 2004-03-11 | インダストリアル リサーチ リミテッド | Titanium-containing materials |
| WO2010055770A1 (en) * | 2008-11-12 | 2010-05-20 | 日産化学工業株式会社 | Titanium oxide sol manufacturing method |
| JP2010195654A (en) * | 2009-02-26 | 2010-09-09 | Fujifilm Corp | Titanium oxide particle dispersion liquid and method of manufacturing the same, and photocatalyst structure |
| JP2013095622A (en) * | 2011-10-28 | 2013-05-20 | Shinshu Univ | Titanium oxide particle for photocatalyst and method for producing the same |
| CN103285852A (en) * | 2013-04-25 | 2013-09-11 | 上海师范大学 | Ti<3+>-self-doped anatase titanium-oxide photocatalyst with large specific surface area, and synthetic method and applications thereof |
| JP2013216858A (en) * | 2012-03-16 | 2013-10-24 | Nippon Shokubai Co Ltd | Metal oxide particle, composition, and method for producing the metal oxide particle |
| JP2014188417A (en) * | 2013-03-26 | 2014-10-06 | Panahome Corp | Method for manufacturing a photocatalyst composition and method for manufacturing a photocatalyst body |
| JP2014201451A (en) * | 2013-04-01 | 2014-10-27 | 大阪瓦斯株式会社 | Titania nanoparticle, dispersion liquid thereof, and titania paste using the titania nanoparticle |
| CN105523583A (en) * | 2014-10-22 | 2016-04-27 | 中国石油化工股份有限公司 | Synthetic method of nano titanium dioxide powder |
-
2018
- 2018-03-29 JP JP2018064190A patent/JP7206056B2/en active Active
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001262007A (en) * | 2000-03-17 | 2001-09-26 | Mitsubishi Gas Chem Co Inc | Titania coating liquid and its production method, and titania film and its formation method |
| JP2004507421A (en) * | 2000-07-17 | 2004-03-11 | インダストリアル リサーチ リミテッド | Titanium-containing materials |
| JP2002320917A (en) * | 2001-04-27 | 2002-11-05 | Toto Ltd | Production method for photocatalytic coating film and photocatalytic material |
| JP2004018477A (en) * | 2002-06-18 | 2004-01-22 | Idemitsu Kosan Co Ltd | Water-soluble titanium compound and method for producing the same |
| WO2010055770A1 (en) * | 2008-11-12 | 2010-05-20 | 日産化学工業株式会社 | Titanium oxide sol manufacturing method |
| JP2010195654A (en) * | 2009-02-26 | 2010-09-09 | Fujifilm Corp | Titanium oxide particle dispersion liquid and method of manufacturing the same, and photocatalyst structure |
| JP2013095622A (en) * | 2011-10-28 | 2013-05-20 | Shinshu Univ | Titanium oxide particle for photocatalyst and method for producing the same |
| JP2013216858A (en) * | 2012-03-16 | 2013-10-24 | Nippon Shokubai Co Ltd | Metal oxide particle, composition, and method for producing the metal oxide particle |
| JP2014188417A (en) * | 2013-03-26 | 2014-10-06 | Panahome Corp | Method for manufacturing a photocatalyst composition and method for manufacturing a photocatalyst body |
| JP2014201451A (en) * | 2013-04-01 | 2014-10-27 | 大阪瓦斯株式会社 | Titania nanoparticle, dispersion liquid thereof, and titania paste using the titania nanoparticle |
| CN103285852A (en) * | 2013-04-25 | 2013-09-11 | 上海师范大学 | Ti<3+>-self-doped anatase titanium-oxide photocatalyst with large specific surface area, and synthetic method and applications thereof |
| CN105523583A (en) * | 2014-10-22 | 2016-04-27 | 中国石油化工股份有限公司 | Synthetic method of nano titanium dioxide powder |
Non-Patent Citations (4)
| Title |
|---|
| JUN, W. Y. ET AL., KOREAN CHEMICAL ENGINEERING RESEARCH, vol. 48, JPN6021043008, 31 August 2010 (2010-08-31), pages 417 - 422, ISSN: 0004629669 * |
| PARRA, R. ET AL., CHEMISTRY OF MATERIALS, vol. 20, JPN6021043009, 20 November 2007 (2007-11-20), pages 143 - 150, ISSN: 0004629668 * |
| TAHERINIA, M. ET AL., IRANIAN JOURNAL OF HYDROGEN & FUEL CELL, vol. 2, JPN6021043010, 2017, pages 139 - 151, ISSN: 0004791796 * |
| YANG, S. ET AL., JOURNAL OF THE AMERICAN CERAMIC SOCIETY, vol. 88, JPN6021043011, 17 March 2005 (2005-03-17), pages 968 - 970, ISSN: 0004791795 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2021154233A (en) * | 2020-03-27 | 2021-10-07 | 大阪瓦斯株式会社 | Metal nanoparticle carrying titania nanoparticle and photocatalyst using the same |
| JP7539780B2 (en) | 2020-03-27 | 2024-08-26 | 大阪瓦斯株式会社 | Titania nanoparticles carrying metal nanoparticles and photocatalysts using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP7206056B2 (en) | 2023-01-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6591948B2 (en) | Zirconium nitride powder and method for producing the same | |
| JP4974459B2 (en) | Support comprising a photocatalytic TiO2 layer | |
| US20180031739A1 (en) | Nanometric tin-containing metal oxide particle and dispersion, and preparation method and application thereof | |
| CN110809561B (en) | Method for producing fine particle dispersion of iron-containing rutile titanium oxide, fine particles of iron-containing rutile titanium oxide, and use thereof | |
| EP1771518A2 (en) | Dispersion containing titanium dioxide | |
| JP6245832B2 (en) | Method for producing titania nanoparticles and titania dispersion | |
| Okunaka et al. | Facile preparation of stable aqueous titania sols for fabrication of highly active TiO 2 photocatalyst films | |
| JP6004418B2 (en) | VO2-containing composition and method for producing VO2-dispersed resin layer | |
| WO2008006566A2 (en) | Stable suspensions of crystalline tio2 particles of hydrothermally treated sol gel precursor powders | |
| JP2019172526A (en) | Titania nanoparticle and ultraviolet shielding material including the same | |
| JP5343604B2 (en) | Method for producing titanium oxide photocatalyst thin film | |
| Beusen et al. | Preparation of a porous nanocrystalline TiO2 layer by deposition of hydrothermally synthesized nanoparticles | |
| JP2022156812A (en) | Method for producing zinc oxide nanoparticle | |
| JP2019171319A (en) | photocatalyst | |
| JP7539780B2 (en) | Titania nanoparticles carrying metal nanoparticles and photocatalysts using the same | |
| JP2005008515A (en) | Metal oxide particle and its manufacturing method | |
| JP2011012233A (en) | Infrared ray-shielding material, coating material for shielding infrared ray, infrared ray-shielding film, and infrared ray-shielding base material | |
| JP2010090011A (en) | Titanium oxide powder, dispersion liquid, and method of producing the titanium oxide powder | |
| DE102006032759B4 (en) | Stable suspensions of crystalline ZrO2 particles from hydrothermally treated sol-gel precursor powders | |
| JP2021154233A (en) | Metal nanoparticle carrying titania nanoparticle and photocatalyst using the same | |
| JP2022156818A (en) | Composite nanoparticle | |
| JP7371638B2 (en) | Surface-treated infrared absorbing fine particle dispersion and method for producing the same | |
| JP6105281B2 (en) | Aluminum pigment composition and method for producing the same | |
| JP2022155211A (en) | Metal-carrying titania nanoparticle, and production method thereof | |
| JP2023147700A (en) | Titania nanoparticle and production method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20201113 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20211011 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20211102 |
|
| A601 | Written request for extension of time |
Free format text: JAPANESE INTERMEDIATE CODE: A601 Effective date: 20211228 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20220228 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20220607 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20220907 |
|
| C60 | Trial request (containing other claim documents, opposition documents) |
Free format text: JAPANESE INTERMEDIATE CODE: C60 Effective date: 20220907 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A821 Effective date: 20220912 |
|
| A911 | Transfer to examiner for re-examination before appeal (zenchi) |
Free format text: JAPANESE INTERMEDIATE CODE: A911 Effective date: 20221003 |
|
| C21 | Notice of transfer of a case for reconsideration by examiners before appeal proceedings |
Free format text: JAPANESE INTERMEDIATE CODE: C21 Effective date: 20221004 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20221206 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20230104 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 7206056 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |