JP2007222725A - Method for improving activity of photocatalytic titanium oxide and method for manufacturing high-activity photocatalytic titanium oxide - Google Patents
Method for improving activity of photocatalytic titanium oxide and method for manufacturing high-activity photocatalytic titanium oxide Download PDFInfo
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- JP2007222725A JP2007222725A JP2006044600A JP2006044600A JP2007222725A JP 2007222725 A JP2007222725 A JP 2007222725A JP 2006044600 A JP2006044600 A JP 2006044600A JP 2006044600 A JP2006044600 A JP 2006044600A JP 2007222725 A JP2007222725 A JP 2007222725A
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- 230000001699 photocatalysis Effects 0.000 title claims abstract description 132
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title claims abstract description 111
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 title claims abstract description 110
- 238000000034 method Methods 0.000 title claims abstract description 45
- 230000000694 effects Effects 0.000 title claims abstract description 38
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 35
- 238000001816 cooling Methods 0.000 claims abstract description 62
- 238000010304 firing Methods 0.000 claims abstract description 23
- 239000002243 precursor Substances 0.000 claims abstract description 22
- 238000010438 heat treatment Methods 0.000 claims abstract description 12
- 239000003054 catalyst Substances 0.000 claims abstract description 11
- 238000007539 photo-oxidation reaction Methods 0.000 claims abstract description 5
- LLZRNZOLAXHGLL-UHFFFAOYSA-J titanic acid Chemical compound O[Ti](O)(O)O LLZRNZOLAXHGLL-UHFFFAOYSA-J 0.000 claims description 17
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 claims description 7
- 239000002253 acid Substances 0.000 claims description 7
- 239000011941 photocatalyst Substances 0.000 claims description 5
- 229910000510 noble metal Inorganic materials 0.000 abstract description 4
- 239000010936 titanium Substances 0.000 description 22
- 229910052719 titanium Inorganic materials 0.000 description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 21
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 19
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 14
- 239000000843 powder Substances 0.000 description 8
- 238000001354 calcination Methods 0.000 description 7
- 229910002092 carbon dioxide Inorganic materials 0.000 description 7
- 239000001569 carbon dioxide Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
- 150000002484 inorganic compounds Chemical class 0.000 description 5
- 229910010272 inorganic material Inorganic materials 0.000 description 5
- 150000002894 organic compounds Chemical class 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- 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 4
- 239000011521 glass Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- -1 titanium hydride Chemical compound 0.000 description 3
- 229910000349 titanium oxysulfate Inorganic materials 0.000 description 3
- IKHGUXGNUITLKF-UHFFFAOYSA-N Acetaldehyde Chemical compound CC=O IKHGUXGNUITLKF-UHFFFAOYSA-N 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 230000002708 enhancing effect Effects 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000010970 precious metal Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- UBZYKBZMAMTNKW-UHFFFAOYSA-J titanium tetrabromide Chemical compound Br[Ti](Br)(Br)Br UBZYKBZMAMTNKW-UHFFFAOYSA-J 0.000 description 2
- OVSGBKZKXUMMHS-VGKOASNMSA-L (z)-4-oxopent-2-en-2-olate;propan-2-olate;titanium(4+) Chemical compound [Ti+4].CC(C)[O-].CC(C)[O-].C\C([O-])=C\C(C)=O.C\C([O-])=C\C(C)=O OVSGBKZKXUMMHS-VGKOASNMSA-L 0.000 description 1
- XAVMMNWPOYCFPU-UHFFFAOYSA-N 2-[bis(2-hydroxyethyl)amino]ethanolate;propan-2-olate;titanium(4+) Chemical compound [Ti+4].CC(C)[O-].CC(C)[O-].OCCN(CCO)CC[O-].OCCN(CCO)CC[O-] XAVMMNWPOYCFPU-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- QYEXBYZXHDUPRC-UHFFFAOYSA-N B#[Ti]#B Chemical compound B#[Ti]#B QYEXBYZXHDUPRC-UHFFFAOYSA-N 0.000 description 1
- MDKXWFMOHAXBTH-UHFFFAOYSA-N CC(C)(C)O[Ti] Chemical compound CC(C)(C)O[Ti] MDKXWFMOHAXBTH-UHFFFAOYSA-N 0.000 description 1
- LLQPHQFNMLZJMP-UHFFFAOYSA-N Fentrazamide Chemical compound N1=NN(C=2C(=CC=CC=2)Cl)C(=O)N1C(=O)N(CC)C1CCCCC1 LLQPHQFNMLZJMP-UHFFFAOYSA-N 0.000 description 1
- CDQFODAJQFUTJR-UHFFFAOYSA-M [NH4+].[O-]C(=O)C(=O)O[Ti] Chemical compound [NH4+].[O-]C(=O)C(=O)O[Ti] CDQFODAJQFUTJR-UHFFFAOYSA-M 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- YWJHUQQPWSXFTC-UHFFFAOYSA-H barium(2+) oxalate titanium(4+) Chemical compound [Ti+4].[Ba++].[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O YWJHUQQPWSXFTC-UHFFFAOYSA-H 0.000 description 1
- 150000003819 basic metal compounds Chemical class 0.000 description 1
- FPCJKVGGYOAWIZ-UHFFFAOYSA-N butan-1-ol;titanium Chemical compound [Ti].CCCCO.CCCCO.CCCCO.CCCCO FPCJKVGGYOAWIZ-UHFFFAOYSA-N 0.000 description 1
- 239000013522 chelant Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- XFVGXQSSXWIWIO-UHFFFAOYSA-N chloro hypochlorite;titanium Chemical compound [Ti].ClOCl XFVGXQSSXWIWIO-UHFFFAOYSA-N 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000004332 deodorization Methods 0.000 description 1
- 230000001877 deodorizing effect Effects 0.000 description 1
- IAOQICOCWPKKMH-UHFFFAOYSA-N dithieno[3,2-a:3',2'-d]thiophene Chemical compound C1=CSC2=C1C(C=CS1)=C1S2 IAOQICOCWPKKMH-UHFFFAOYSA-N 0.000 description 1
- XGZNHFPFJRZBBT-UHFFFAOYSA-N ethanol;titanium Chemical compound [Ti].CCO.CCO.CCO.CCO XGZNHFPFJRZBBT-UHFFFAOYSA-N 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 125000003253 isopropoxy group Chemical group [H]C([H])([H])C([H])(O*)C([H])([H])[H] 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- ZEIWWVGGEOHESL-UHFFFAOYSA-N methanol;titanium Chemical compound [Ti].OC.OC.OC.OC ZEIWWVGGEOHESL-UHFFFAOYSA-N 0.000 description 1
- 235000019645 odor Nutrition 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- HQASLXJEKYYFNY-UHFFFAOYSA-N selenium(2-);titanium(4+) Chemical compound [Ti+4].[Se-2].[Se-2] HQASLXJEKYYFNY-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000001954 sterilising effect Effects 0.000 description 1
- 238000004659 sterilization and disinfection Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- RCYJPSGNXVLIBO-UHFFFAOYSA-N sulfanylidenetitanium Chemical compound [S].[Ti] RCYJPSGNXVLIBO-UHFFFAOYSA-N 0.000 description 1
- 150000003609 titanium compounds Chemical class 0.000 description 1
- 229910000048 titanium hydride Inorganic materials 0.000 description 1
- 229910000348 titanium sulfate Inorganic materials 0.000 description 1
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 description 1
- NLLZTRMHNHVXJJ-UHFFFAOYSA-J titanium tetraiodide Chemical compound I[Ti](I)(I)I NLLZTRMHNHVXJJ-UHFFFAOYSA-J 0.000 description 1
- 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 1
- YONPGGFAJWQGJC-UHFFFAOYSA-K titanium(iii) chloride Chemical compound Cl[Ti](Cl)Cl YONPGGFAJWQGJC-UHFFFAOYSA-K 0.000 description 1
- MTPVUVINMAGMJL-UHFFFAOYSA-N trimethyl(1,1,2,2,2-pentafluoroethyl)silane Chemical compound C[Si](C)(C)C(F)(F)C(F)(F)F MTPVUVINMAGMJL-UHFFFAOYSA-N 0.000 description 1
- 238000005406 washing Methods 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
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- Catalysts (AREA)
Abstract
Description
本発明は、光触媒酸化チタンの光触媒活性を向上させる方法と、これを用いた高活性光触媒酸化チタンの製造方法とに関する。詳しくは、本発明の光触媒酸化チタンの活性向上方法および高活性光触媒酸化チタンの製造方法は、例えば、製造時に充分な光触媒活性が付与されなかった光触媒酸化チタンにより高い光触媒活性を付与する場合などに有用な方法である。 The present invention relates to a method for improving the photocatalytic activity of photocatalytic titanium oxide and a method for producing highly active photocatalytic titanium oxide using the method. Specifically, the photocatalytic titanium oxide activity improving method and the highly active photocatalytic titanium oxide production method of the present invention are, for example, when high photocatalytic activity is imparted by photocatalytic titanium oxide that was not imparted with sufficient photocatalytic activity during production. This is a useful method.
光触媒酸化チタンは、酸化チタンを主成分とし、光触媒活性を示す物質であり、その光触媒作用は、例えば脱臭や殺菌等を目的とした様々な分野で利用されている。
従来、光触媒酸化チタンの製造方法としては、水酸化チタンのような光触媒酸化チタン前駆体を焼成する方法などが知られている（特許文献１参照）。ところが、このような従来の方法においては、製造時に得られる触媒の一部もしくは全部に充分な光触媒活性が付与されず、活性が不充分であったり、活性にばらつきが生じたりすることがあった。そのような触媒は通常不良品として処分されることになるが、既に有している光触媒活性をさらに高める処理を施すことができれば、これらを有効に利用することが可能になる。
Photocatalytic titanium oxide is a substance having titanium oxide as a main component and exhibiting photocatalytic activity, and its photocatalytic action is used in various fields for the purpose of deodorization and sterilization, for example.
Conventionally, as a method for producing photocatalytic titanium oxide, a method of firing a photocatalytic titanium oxide precursor such as titanium hydroxide is known (see Patent Document 1). However, in such a conventional method, sufficient photocatalytic activity is not imparted to a part or all of the catalyst obtained at the time of production, and the activity may be insufficient or the activity may vary. . Such a catalyst is usually disposed of as a defective product, but if it can be subjected to a treatment that further increases the photocatalytic activity that it already has, it can be used effectively.
従来から、光触媒活性を向上させる方法としては、酸化物に貴金属を担持させる方法が知られている。例えば、酸化チタンに金を添着させてアルデヒド類の悪臭を効果的に脱臭する技術が開示されている（特許文献２参照）。 Conventionally, as a method of improving the photocatalytic activity, a method of supporting a noble metal on an oxide is known. For example, a technique for effectively deodorizing odors of aldehydes by attaching gold to titanium oxide has been disclosed (see Patent Document 2).
しかしながら、前述した従来の光触媒活性向上方法においては、用いる貴金属が一般に高価な素材であるためにコスト的な不利益が大きく、貴金属を使用しないで安価に光触媒活性を向上させうる方法が求められていた。
また、従来の光触媒酸化チタンの製造方法における問題、すなわち得られる触媒の活性が不充分であったり、活性にばらつきが生じたりするという問題に関しては、製造時において得られる触媒に従来よりも高い光触媒活性が付与されるようにすることで、解決できると考えられる。しかし、これまで知られた光触媒酸化チタンの製造方法では、充分に高い光触媒活性が付与された触媒は得られていなかった。
However, the conventional photocatalytic activity improving method described above has a large cost disadvantage because the precious metal used is generally an expensive material, and a method that can improve the photocatalytic activity inexpensively without using the precious metal is required. It was.
In addition, regarding the problem in the conventional photocatalytic titanium oxide production method, that is, the problem that the activity of the obtained catalyst is insufficient or the activity varies, the catalyst obtained at the time of production is higher than the conventional photocatalyst. It is thought that it can be solved by imparting activity. However, the conventionally known photocatalytic titanium oxide production methods have not provided a catalyst with sufficiently high photocatalytic activity.
そこで、本発明の課題は、貴金属を使用することのない安価で簡便な処理により光触媒活性を格段に向上させることができる光触媒酸化チタンの活性向上方法と、高い活性を有する光触媒酸化チタンを安価で簡便に得ることができる高活性光触媒酸化チタンの製造方法とを提供することにある。 Therefore, an object of the present invention is to provide a method for improving the activity of photocatalytic titanium oxide that can remarkably improve the photocatalytic activity by an inexpensive and simple treatment without using a noble metal, and a photocatalytic titanium oxide having high activity at a low cost. An object of the present invention is to provide a method for producing a highly active photocatalytic titanium oxide that can be easily obtained.
本発明者らは、上記課題を解決するべく鋭意研究を重ねた結果、活性を向上させようとする光触媒酸化チタン（または、光触媒酸化チタン前駆体を焼成、冷却することにより得られた光触媒酸化チタン）を焼成温度まで再加熱し、その後の冷却において冷却速度を特定範囲に調整することによって、前記課題を一挙に解決しうることを見出し、本発明を完成させるに至った。 As a result of intensive studies to solve the above-mentioned problems, the present inventors have developed photocatalytic titanium oxide (or photocatalytic titanium oxide obtained by firing and cooling a photocatalytic titanium oxide precursor) to improve the activity. ) Was reheated to the calcination temperature, and the cooling rate was adjusted to a specific range in the subsequent cooling, and it was found that the above problems could be solved at once, and the present invention was completed.
すなわち、本発明は以下の構成からなる。
（１）光触媒酸化チタンの光触媒活性を向上させる方法であって、光触媒酸化チタンを焼成温度まで加熱したのち冷却速度１５０℃／時間以下で冷却する、ことを特徴とする光触媒酸化チタンの活性向上方法。
（２）３００℃以上の温度から１００℃以下の温度にまで冷却する、前記（１）記載の光触媒酸化チタンの活性向上方法。
（３）光触媒酸化チタンは、水酸化チタン、オルトチタン酸、メタチタン酸および窒化チタンからなる群から選ばれる少なくとも１種を前駆体とするものである、前記（１）または（２）記載の光触媒酸化チタンの活性向上方法。
（４）光触媒酸化チタン前駆体を焼成、冷却することにより光酸化触媒酸化チタンを得る工程（Ｉ）と、前記工程（Ｉ）で得られた光触媒酸化チタンを焼成温度まで加熱したのち冷却速度１５０℃／時間以下で冷却することにより光触媒活性を向上させる工程（ＩＩ）とを含む、高活性光触媒酸化チタンの製造方法。
（５）前記工程（ＩＩ）において３００℃以上の温度から１００℃以下の温度にまで冷却する、前記（４）記載の高活性光触媒酸化チタンの製造方法。
（６）前記光触媒酸化チタン前駆体は、水酸化チタン、オルトチタン酸、メタチタン酸および窒化チタンからなる群から選ばれる少なくとも１種である、前記（４）または（５）記載の高活性光触媒酸化チタンの製造方法。
That is, the present invention has the following configuration.
(1) A method for improving the photocatalytic activity of photocatalytic titanium oxide, wherein the photocatalytic titanium oxide is heated to a firing temperature and then cooled at a cooling rate of 150 ° C./hour or less. .
(2) The method for improving the activity of the photocatalytic titanium oxide according to (1), wherein the cooling is performed from a temperature of 300 ° C. or higher to a temperature of 100 ° C. or lower.
(3) The photocatalytic titanium oxide is a photocatalyst according to the above (1) or (2), wherein the photocatalytic titanium oxide is a precursor of at least one selected from the group consisting of titanium hydroxide, orthotitanic acid, metatitanic acid, and titanium nitride. A method for improving the activity of titanium oxide.
(4) Step (I) of obtaining photooxidation-catalyzed titanium oxide by firing and cooling the photocatalyst titanium oxide precursor, and heating the photocatalytic titanium oxide obtained in the step (I) to the firing temperature, and then cooling rate 150 And a step (II) for improving the photocatalytic activity by cooling at a temperature not higher than ° C./hour, and a method for producing a highly active photocatalytic titanium oxide.
(5) The method for producing highly active photocatalytic titanium oxide according to (4), wherein the cooling is performed from a temperature of 300 ° C. or higher to a temperature of 100 ° C. or lower in the step (II).
(6) The highly active photocatalytic oxidation according to (4) or (5), wherein the photocatalytic titanium oxide precursor is at least one selected from the group consisting of titanium hydroxide, orthotitanic acid, metatitanic acid, and titanium nitride. A method for producing titanium.
本発明によれば、貴金属を使用することのない安価で簡便な処理により光触媒酸化チタンの光触媒活性を格段に向上させることができる、という効果がある。それによって、例えば、製造時に充分な光触媒活性が付与されなかった光触媒酸化チタンにより高い光触媒活性を付与することが可能になる。また、本発明によれば、製造時において充分に高い光触媒活性が付与された触媒を安価で簡便に得ることができる、という効果がある。それによって、触媒の活性が不充分であったり、活性にばらつきが生じたりするという従来の問題を容易に回避することができる。 According to the present invention, there is an effect that the photocatalytic activity of the photocatalytic titanium oxide can be remarkably improved by an inexpensive and simple treatment without using a noble metal. Thereby, for example, it becomes possible to impart high photocatalytic activity to photocatalytic titanium oxide that was not imparted with sufficient photocatalytic activity during production. In addition, according to the present invention, there is an effect that a catalyst imparted with a sufficiently high photocatalytic activity at the time of production can be easily obtained at low cost. Thereby, it is possible to easily avoid the conventional problem that the activity of the catalyst is insufficient or the activity varies.
［光触媒酸化チタンの活性向上方法］
本発明の光触媒酸化チタンの活性向上方法（以下「本発明の活性向上方法」と称することもある。）は、光触媒酸化チタンを焼成温度まで加熱したのち、冷却速度１５０℃／時間以下で冷却することにより、光触媒酸化チタンの光触媒活性を向上させる方法である。
[Method for improving photocatalytic titanium oxide activity]
The photocatalytic titanium oxide activity enhancing method of the present invention (hereinafter sometimes referred to as “the activity enhancing method of the present invention”) is heated to a firing temperature and then cooled at a cooling rate of 150 ° C./hour or less. Thus, the photocatalytic activity of the photocatalytic titanium oxide is improved.
光触媒酸化チタンを焼成温度まで加熱するとは、言い換えれば、光触媒酸化チタンを再焼成することである（以下、ここで言う「加熱」のことを「再焼成」と称することもある）。したがって、ここで言う焼成温度とは、光触媒酸化チタンの焼成が可能な温度を意味するものである。具体的には、前記焼成温度は、通常、好ましくは２００〜８００℃、より好ましくは３００〜６００℃とするのがよい。また、このような焼成温度にまで加熱するのに要する時間は、通常、０．１〜３０時間程度であるのがよい。
加熱に用いられる装置は、特に制限はないが、例えば、熱風循環式焼成炉、静置式焼成炉、トンネル炉、ロータリーキルン、遠赤外線炉、マイクロ波加熱炉等を使用することができる。
In other words, heating the photocatalytic titanium oxide to the calcination temperature means refiring the photocatalytic titanium oxide (hereinafter, “heating” referred to herein may be referred to as “refiring”). Therefore, the calcination temperature here means a temperature at which the photocatalytic titanium oxide can be calcinated. Specifically, the firing temperature is usually preferably 200 to 800 ° C, more preferably 300 to 600 ° C. The time required for heating to such a firing temperature is usually about 0.1 to 30 hours.
The apparatus used for heating is not particularly limited, and for example, a hot-air circulating firing furnace, a stationary firing furnace, a tunnel furnace, a rotary kiln, a far infrared furnace, a microwave heating furnace, or the like can be used.
冷却に際しては、冷却速度を特定範囲に制御することが重要である。すなわち、冷却速度は１５０℃／時間以下でなければならず、好ましくは５〜１５０℃／時間、より好ましくは１０〜１００℃／時間、さらに好ましくは１０〜５０℃／時間で冷却するのがよい。冷却速度が１５０℃／時間を超えると、良好な光触媒活性が均一に安定して付与できない。また、冷却速度が５℃／時間を下回ると、生産性が低下するので好ましくない。 When cooling, it is important to control the cooling rate within a specific range. That is, the cooling rate must be 150 ° C./hour or less, preferably 5 to 150 ° C./hour, more preferably 10 to 100 ° C./hour, and still more preferably 10 to 50 ° C./hour. . When the cooling rate exceeds 150 ° C./hour, good photocatalytic activity cannot be imparted uniformly and stably. On the other hand, when the cooling rate is less than 5 ° C./hour, productivity is lowered, which is not preferable.
冷却に際しては、３００℃以上の温度から１００℃以下の温度にまで冷却することが好ましい。すなわち、前記冷却速度での冷却の開始温度は３００℃以上であることが好ましく、前記冷却速度での冷却の終了温度が１００℃以下であることが好ましいのである。前記冷却速度での冷却の開始温度が３００℃未満であったり、前記冷却速度での冷却の終了温度が１００℃を超える温度であると、充分な触媒活性が発現されない恐れがある。 In cooling, it is preferable to cool from a temperature of 300 ° C. or higher to a temperature of 100 ° C. or lower. That is, the cooling start temperature at the cooling rate is preferably 300 ° C. or higher, and the cooling end temperature at the cooling rate is preferably 100 ° C. or lower. If the cooling start temperature at the cooling rate is less than 300 ° C. or the cooling end temperature at the cooling rate is higher than 100 ° C., sufficient catalytic activity may not be exhibited.
本発明の活性向上方法においては、前記再焼成の際には、再焼成に供する光触媒酸化チタン（以下「被焼成物」と称することもある）が水と接触することのないように焼成を行ない、かつ、前記冷却の際には、温度が１００〜６００℃の範囲となっている間に前記被焼成物を水分と接触させる、ことが好ましい。このような態様によれば、より一層光触媒活性を向上させることができる。 In the activity improving method of the present invention, at the time of re-firing, the photocatalytic titanium oxide used for re-firing (hereinafter also referred to as “substance to be fired”) is fired so as not to come into contact with water. And in the case of the said cooling, it is preferable to make the said to-be-baked object contact with a water | moisture content while the temperature is the range of 100-600 degreeC. According to such an embodiment, the photocatalytic activity can be further improved.
再焼成の際に、前記被焼成物が水と接触することのないようにするには、例えば、実質的に水蒸気を含まない乾燥状態の雰囲気中（具体的には、水蒸気濃度が２ｖｏｌ％未満、より好ましくは１ｖｏｌ％以下、さらに好ましくは０ｖｏｌ％である雰囲気中）で再焼成を行なうようにすればよい。
なお、再焼成を行なう際の雰囲気ガスは、大気であってもよいし、アルゴンなどの希ガスや窒素ガスなどの不活性ガスであってもよい。
In order to prevent the material to be fired from coming into contact with water during refiring, for example, in a dry atmosphere substantially free from water vapor (specifically, the water vapor concentration is less than 2 vol%). More preferably, re-baking may be performed in an atmosphere of 1 vol% or less, more preferably 0 vol%.
Note that the atmosphere gas at the time of refiring may be air, or may be a rare gas such as argon or an inert gas such as nitrogen gas.
冷却の際に、温度が１００〜６００℃の範囲となっている間に前記被焼成物を水分と接触させるには、通常、雰囲気中の水蒸気濃度を２〜８０ｖｏｌ％、好ましくは６０ｖｏｌ％以下とすればよい。ここで、水蒸気濃度を上記範囲にするには、例えば、炉内に水蒸気（スチーム）を雰囲気ガスとともに吹き込み、置換すればよい。前記被焼成物を水分と接触させる際の時間は、通常、０．１時間〜１時間程度とすればよい。
冷却の際に、被焼成物と水分とを接触させる場合、冷却前後の温度差は、通常３０〜２００℃、好ましくは５０〜２００℃となるようにするのがよい。
なお、冷却する際の雰囲気ガスは、大気であってもよいし、アルゴンなどの希ガスや窒素ガスなどの不活性ガスであってもよい。
In order to bring the object to be fired into contact with moisture while the temperature is in the range of 100 to 600 ° C. during cooling, the water vapor concentration in the atmosphere is usually 2 to 80 vol%, preferably 60 vol% or less. do it. Here, in order to bring the water vapor concentration into the above range, for example, water vapor (steam) may be blown into the furnace together with the atmospheric gas and replaced. The time for bringing the object to be fired into contact with moisture is usually about 0.1 hour to 1 hour.
When the object to be fired and moisture are brought into contact with each other during cooling, the temperature difference before and after cooling is usually 30 to 200 ° C, preferably 50 to 200 ° C.
The atmosphere gas for cooling may be air, or may be a rare gas such as argon or an inert gas such as nitrogen gas.
本発明の活性向上方法に供する光触媒酸化チタンは、光触媒活性を有する酸化チタン（好ましくは、アナターゼ型酸化チタン）であればよい。したがって、本発明の活性向上方法に供する光触媒酸化チタンは、どのような前駆体に由来するものか（言い換えれば、どのような前駆体を焼成してなるものか）は問わないが、光触媒酸化チタンの前駆体としては、例えば、以下のチタン含有無機化合物やチタン含有有機化合物等が挙げられる。 The photocatalytic titanium oxide used in the activity improving method of the present invention may be any titanium oxide (preferably anatase type titanium oxide) having photocatalytic activity. Therefore, it does not matter what precursor the photocatalytic titanium oxide used in the method for improving the activity of the present invention is derived from (in other words, what precursor is calcined), but the photocatalytic titanium oxide does not matter. Examples of the precursor include the following titanium-containing inorganic compounds and titanium-containing organic compounds.
チタン含有無機化合物としては、例えば、窒化チタン、ホウ化チタン、臭化チタン、炭化チタン、水素化チタン、ヨウ化チタン、水酸化チタン、セレン化チタン、硫化チタン、テルル化チタン、硫酸チタン〔Ｔｉ（ＳＯ4）2・ｍＨ2Ｏ、０≦ｍ≦２０〕、オキシ硫酸チタン〔ＴｉＯＳＯ4・ｎＨ2Ｏ、０≦ｎ≦２０〕、三塩化チタン〔ＴｉＣｌ3〕、四塩化チタン〔ＴｉＣｌ4〕、オキシ塩化チタン〔ＴｉＯＣｌ2〕、四臭化チタン〔ＴｉＢｒ4〕、シュウ酸チタンアンモニウム、シュウ酸チタンバリウム、オルトチタン酸、メタチタン酸などが挙げられる。チタン含有有機化合物としては、例えば、テトラメトキシチタン、テトラエトキシチタン、テトラ−ｎ−プロポキシチタン、テトライソプロポキシチタン、テトラ−ｎ−ブトキシチタン、テトライソブトキシチタン、テトラ−ｓｅｃ−ブトキシチタン、テトラ−ｔ−ブトキシチタン、テトラキス−２−エチルヘキシロキシチタン、テトラステアリロキシチタンのようなテトラアルコキシチタン化合物、ジイソプロポキシビス（アセチルアセトナト）チタン、ジイソプロポキシビス（トリエタノールアミナト）チタン、ジ−ｎ−ブトキシビス（トリエタノールアミナト）チタン、ジ（２−エチルヘキシロキシ）ビス（２−エチル−１，３−ヘキサンジオラト）チタン、イソプロポキシ（２−エチルヘキサンジオラト）チタン、テトラアセチルアセトネートチタン、ヒドロキシビス（ラクタト）チタンのようなチタンキレート化合物などが挙げられる。これらチタン含有無機化合物やチタン含有有機化合物は、一部が加水分解されていてもよいし、一部が結晶性酸化チタンに結晶化していてもよい。 Examples of the titanium-containing inorganic compound include titanium nitride, titanium boride, titanium bromide, titanium carbide, titanium hydride, titanium iodide, titanium hydroxide, titanium selenide, titanium sulfide, titanium telluride, titanium sulfate [Ti (SO 4 ) 2 · mH 2 O, 0 ≦ m ≦ 20], titanium oxysulfate [TiOSO 4 .nH 2 O, 0 ≦ n ≦ 20], titanium trichloride [TiCl 3 ], titanium tetrachloride [TiCl 4 ] , Titanium oxychloride [TiOCl 2 ], titanium tetrabromide [TiBr 4 ], titanium ammonium oxalate, barium titanium oxalate, orthotitanic acid, metatitanic acid and the like. Examples of the titanium-containing organic compound include tetramethoxy titanium, tetraethoxy titanium, tetra-n-propoxy titanium, tetraisopropoxy titanium, tetra-n-butoxy titanium, tetraisobutoxy titanium, tetra-sec-butoxy titanium, tetra- Tetraalkoxy titanium compounds such as t-butoxy titanium, tetrakis-2-ethylhexyloxy titanium, tetrastearyloxy titanium, diisopropoxybis (acetylacetonato) titanium, diisopropoxybis (triethanolaminato) titanium, di -N-butoxybis (triethanolaminato) titanium, di (2-ethylhexyloxy) bis (2-ethyl-1,3-hexanediolato) titanium, isopropoxy (2-ethylhexanediolato) titanium, tetraacetyl A Tonetochitan, hydroxy bis (lactato) titanium chelate compounds such as titanium and the like. These titanium-containing inorganic compounds and titanium-containing organic compounds may be partly hydrolyzed or partly crystallized into crystalline titanium oxide.
本発明の活性向上方法は、上記のチタン含有無機化合物やチタン含有有機化合物の中でも特に、水酸化チタン、オルトチタン酸、メタチタン酸および窒化チタンからなる群から選ばれる少なくとも１種を前駆体として得られた光触媒酸化チタンに適用するのが好ましい。 The activity improving method of the present invention obtains, as a precursor, at least one selected from the group consisting of titanium hydroxide, orthotitanic acid, metatitanic acid and titanium nitride, among the above-mentioned titanium-containing inorganic compounds and titanium-containing organic compounds. It is preferable to apply to the obtained photocatalytic titanium oxide.
［高活性光触媒酸化チタンの製造方法］
本発明の高活性光触媒酸化チタンの製造方法（以下「本発明の製造方法」と称することもある。）は、光酸化触媒酸化チタンを得る工程（Ｉ）と、前記工程（Ｉ）で得られた光触媒酸化チタンの光触媒活性を向上させる工程（ＩＩ）とを含む。以下、両工程について各々説明する。
[Method for producing highly active photocatalytic titanium oxide]
The production method of the highly active photocatalytic titanium oxide of the present invention (hereinafter sometimes referred to as “the production method of the present invention”) is obtained by the step (I) of obtaining the photooxidation catalytic titanium oxide and the step (I). And (II) improving the photocatalytic activity of the photocatalytic titanium oxide. Hereinafter, both steps will be described.
前記工程（Ｉ）は、光触媒酸化チタン前駆体から光触媒酸化チタンを得る工程であり、光触媒酸化チタン前駆体を焼成したのち冷却する。
前記工程（Ｉ）で用いる光触媒酸化チタン前駆体としては、［光触媒酸化チタンの活性向上方法］の項で前述したチタン含有無機化合物やチタン含有有機化合物等が挙げられる。それらの中でも特に、水酸化チタン、オルトチタン酸、メタチタン酸および窒化チタンからなる群から選ばれる少なくとも１種が好ましい。
The step (I) is a step of obtaining photocatalytic titanium oxide from the photocatalytic titanium oxide precursor, and the photocatalytic titanium oxide precursor is fired and then cooled.
Examples of the photocatalytic titanium oxide precursor used in the step (I) include the titanium-containing inorganic compounds and titanium-containing organic compounds described above in the section [Method for improving activity of photocatalytic titanium oxide]. Among these, at least one selected from the group consisting of titanium hydroxide, orthotitanic acid, metatitanic acid and titanium nitride is particularly preferable.
前記工程（Ｉ）における焼成は、通常、好ましくは３００〜５００℃、より好ましくは３３０〜４５０℃で行われる。また、焼成に要する時間は、１時間〜２４時間とすることが好ましい。ここで、焼成に用いることのできる装置は、［光触媒酸化チタンの活性向上方法］の項で加熱に用いられる装置として前述したものと同様である。 The firing in the step (I) is usually performed at 300 to 500 ° C, more preferably 330 to 450 ° C. In addition, the time required for firing is preferably 1 hour to 24 hours. Here, the apparatus that can be used for the firing is the same as that described above as the apparatus used for heating in the section [Method for improving activity of photocatalytic titanium oxide].
前記工程（Ｉ）における冷却については、冷却速度を含め何ら制限されるものではない。この場合の冷却は、大気中で放冷するなどの手段によって行なわれるのが一般的であり、このような手段によると冷却速度は通常６００〜６５０℃／時間程度である。勿論、該工程（Ｉ）における冷却を１５０℃／時間以下の冷却速度で行なっても構わない。 The cooling in the step (I) is not limited at all including the cooling rate. The cooling in this case is generally performed by means such as cooling in the atmosphere, and according to such means, the cooling rate is usually about 600 to 650 ° C./hour. Of course, the cooling in the step (I) may be performed at a cooling rate of 150 ° C./hour or less.
前記工程（Ｉ）における焼成、冷却は、［光触媒酸化チタンの活性向上方法］の項で前述した再焼成および冷却の際の好ましい態様と同様に、被焼成物（ここでは、光触媒酸化チタン前駆体）が水と接触することのないように焼成を行ない、温度が１００〜６００℃の範囲となっている間に被焼成物を水分と接触させる態様が好ましい。該態様についての詳細については、［光触媒酸化チタンの活性向上方法］の項で前述した説明が同様に適用できる。 The calcination and cooling in the step (I) are carried out in the same manner as in the preferred embodiment in the refiring and cooling described above in the section [Method for improving the activity of photocatalytic titanium oxide] (here, photocatalytic titanium oxide precursor). ) Is performed so that it does not come into contact with water, and the material to be fired is brought into contact with moisture while the temperature is in the range of 100 to 600 ° C. As for the details of the embodiment, the explanation described above in the section of [Method of improving activity of photocatalytic titanium oxide] can be similarly applied.
前記工程（ＩＩ）では、前記工程（Ｉ）で得られた光触媒酸化チタンの光触媒活性を向上させるために、光触媒酸化チタンを焼成温度まで加熱し、その後、冷却速度１５０℃／時間以下で冷却する。すなわち、該工程（ＩＩ）においては、前述した本発明の活性向上方法を実施する。冷却速度の好ましい範囲や、３００℃以上の温度から１００℃以下の温度にまで冷却するのが好ましいこと、を含め、詳細については［光触媒酸化チタンの活性向上方法］の項で前述した通りである。 In the step (II), in order to improve the photocatalytic activity of the photocatalytic titanium oxide obtained in the step (I), the photocatalytic titanium oxide is heated to a calcination temperature and then cooled at a cooling rate of 150 ° C./hour or less. . That is, in the step (II), the above-described activity improving method of the present invention is carried out. The details are as described above in the section [Method for improving activity of photocatalytic titanium oxide], including the preferable range of the cooling rate and the preferable cooling from a temperature of 300 ° C. or higher to a temperature of 100 ° C. or lower. .
本発明の製造方法においては、焼成に供する前の光触媒酸化チタン前駆体もしくは焼成後の酸化チタンに対して、洗浄を施すことが好ましい。さらには、洗浄を施した後には、乾燥を行なうことが好ましく、例えば洗浄した光触媒酸化チタン前駆体は、乾燥後に焼成に供することが好ましい。ここで、乾燥は、通常、好ましくは１０〜２００℃、より好ましくは７０〜１５０℃の温度で行われる。乾燥時間は、乾燥温度に応じて適宜設定すればよいのであるが、通常、１〜２４時間が好ましく、より好ましくは５〜２４時間である。
本発明の製造方法においては、必要に応じて、工程（Ｉ）の後または工程（ＩＩ）の後に得られた光触媒酸化チタンに対して、酸性金属酸化物および／または塩基性金属化合物を表面被覆する処理（表面被覆処理）を施してもよいし、解砕処理を施してもよい。
In the production method of the present invention, it is preferable to wash the photocatalytic titanium oxide precursor before being subjected to calcination or the titanium oxide after calcination. Furthermore, it is preferable to dry after washing, for example, the washed photocatalytic titanium oxide precursor is preferably subjected to firing after drying. Here, drying is usually performed at a temperature of preferably 10 to 200 ° C, more preferably 70 to 150 ° C. The drying time may be appropriately set according to the drying temperature, but is usually preferably 1 to 24 hours, and more preferably 5 to 24 hours.
In the production method of the present invention, if necessary, an acidic metal oxide and / or a basic metal compound is surface-coated on the photocatalytic titanium oxide obtained after step (I) or after step (II). The process (surface coating process) to perform may be given, and a crushing process may be given.
本発明の活性向上方法により光触媒活性が高められた光触媒酸化チタン、および、本発明の製造方法により得られた高活性光触媒酸化チタンは、いずれも高い光触媒活性を示す。 Both the photocatalytic titanium oxide whose photocatalytic activity is enhanced by the activity improving method of the present invention and the highly active photocatalytic titanium oxide obtained by the production method of the present invention exhibit high photocatalytic activity.
以下、実施例および比較例を挙げて本発明を詳細に説明するが、本発明は以下の実施例に限定されるものではない。
なお、得られた光触媒酸化チタンの光触媒活性は以下の方法で評価した。
EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited to a following example.
The photocatalytic activity of the obtained photocatalytic titanium oxide was evaluated by the following method.
＜光触媒活性＞
直径８ｃｍ、高さ１０ｃｍ、容量約０．５Ｌ（５００ｃｍ3）の密閉式ガラス製反応容器内に、直径５ｃｍのガラス製シャーレを載置し、その上に試料とする光触媒酸化チタン０．３ｇを載せ、反応容器内を酸素／窒素混合ガス（酸素／窒素＝１：４（体積比））で満たし、さらにアセトアルデヒド１３．４μモルを封入したのち、反応容器の外側から可視光を照射した。可視光は、５００Ｗキセノンランプ（ウシオ電機社製「ランプＵＸＬ−５００ＳＸ」）を取付けた光源装置（ウシオ電機社製「オプティカルモジュレックスＳＸ−Ｕ１５００ＸＱ」）から、波長４３０ｎｍ以下の紫外線を遮蔽する紫外線カットフィルター（旭テクノガラス社製「Ｙ−４５」）を通して照射した。可視光を照射している間、反応容器内の二酸化炭素の濃度を光音響マルチガスモニタ（ＩＮＮＯＶＡ社製「１２１３型」）により測定し、光触媒酸化チタン１ｇあたりの二酸化炭素生成速度を求めた。この二酸化炭素生成速度が大きいほど、光触媒活性が高いと言える。
<Photocatalytic activity>
A glass petri dish with a diameter of 5 cm is placed in a sealed glass reaction vessel having a diameter of 8 cm, a height of 10 cm, and a capacity of about 0.5 L (500 cm 3 ), and 0.3 g of photocatalytic titanium oxide as a sample is placed thereon. The reaction vessel was filled with an oxygen / nitrogen mixed gas (oxygen / nitrogen = 1: 4 (volume ratio)), and 13.4 μmol of acetaldehyde was further sealed, and then visible light was irradiated from the outside of the reaction vessel. Visible light is cut from ultraviolet light with a wavelength of 430 nm or less from a light source device (USHIO ELECTRIC "Optical Modlex SX-U1500XQ") equipped with a 500W xenon lamp (USHIO ELECTRIC "LAMP UXL-500SX"). Irradiated through a filter ("Y-45" manufactured by Asahi Techno Glass). During irradiation with visible light, the concentration of carbon dioxide in the reaction vessel was measured with a photoacoustic multigas monitor (“1213 type” manufactured by INNOVA) to determine the carbon dioxide production rate per gram of photocatalytic titanium oxide. It can be said that the higher the carbon dioxide production rate, the higher the photocatalytic activity.
（製造例−光触媒酸化チタン前駆体の製造）
オキシ硫酸チタン（添川理化学社製）９０ｇを純水３６０ｇに溶解させて水溶液とし、氷冷下に撹拌しながら２５％アンモニア水（和光純薬工業社製；試薬１級品）１０４ｇを５ｍＬ／分の添加速度で加えることによりオキシ硫酸チタンを加水分解させて、スラリーを得た。このスラリーを濾過して固形分を得、温水で洗浄したのち１００℃で乾燥して、光触媒酸化チタン前駆体としての水酸化チタン粉末を得た。
(Production Example-Production of Photocatalytic Titanium Oxide Precursor)
90 g of titanium oxysulfate (manufactured by Soekawa Rikagaku) was dissolved in 360 g of pure water to obtain an aqueous solution, and 104 g of 25% aqueous ammonia (manufactured by Wako Pure Chemical Industries, Ltd .; reagent grade 1 product) was stirred at 5 mL / min while stirring under ice cooling The slurry was obtained by hydrolyzing the titanium oxysulfate by adding at the addition rate of. This slurry was filtered to obtain a solid content, washed with warm water, and then dried at 100 ° C. to obtain titanium hydroxide powder as a photocatalytic titanium oxide precursor.
（実施例１）
製造例で得られた水酸化チタン粉末を炉内に入れ、２００℃／時間の昇温速度で３４０℃まで昇温し、同温度で１時間保持することにより焼成した。焼成は、水蒸気濃度０ｖｏｌ％の乾燥大気中で行った。その後、同じ雰囲気下に２００℃／時間の冷却速度で８０℃まで冷却して、粉末状の光触媒酸化チタンを得た（ここまでの工程を工程（Ｉ）と称する）。工程（Ｉ）で得られた光触媒酸化チタンの光触媒活性を評価したところ、二酸化炭素生成速度は１ｇあたり５．６μモル／時間であった。
(Example 1)
The titanium hydroxide powder obtained in the production example was put in a furnace, heated to 340 ° C. at a temperature increase rate of 200 ° C./hour, and calcined by holding at that temperature for 1 hour. Firing was performed in a dry atmosphere with a water vapor concentration of 0 vol%. Then, it cooled to 80 degreeC by the cooling rate of 200 degreeC / hour in the same atmosphere, and obtained the powdery photocatalytic titanium oxide (the process so far is called process (I)). When the photocatalytic activity of the photocatalytic titanium oxide obtained in the step (I) was evaluated, the carbon dioxide production rate was 5.6 μmol / hour per 1 g.
工程（Ｉ）で得た光触媒酸化チタン粉末を炉内で水蒸気濃度０ｖｏｌ％の大気中、２００℃／時間の昇温速度で３４０℃まで昇温し、同温度を１時間保持した後、同じ雰囲気下で２０℃／時間の冷却速度で冷却を開始した。３２０℃まで冷却した時点で、炉内に水蒸気濃度３０ｖｏｌ％の大気を導入して炉内を置換し、さらに２００℃まで冷却した時点で、再び水蒸気濃度０ｖｏｌ％の大気を炉内に導入して置換した。５０℃まで冷却した後、光触媒酸化チタン粉末を取り出した（ここまでの工程を工程（ＩＩ）と称する）。工程（ＩＩ）で得られた光触媒酸化チタンの光触媒活性を評価したところ、二酸化炭素生成速度は１ｇあたり７.８μモル／時間であった。 The photocatalytic titanium oxide powder obtained in the step (I) was heated to 340 ° C. at a rate of temperature increase of 200 ° C./hour in an atmosphere with a water vapor concentration of 0 vol% in the furnace, and the same atmosphere was maintained after maintaining the same temperature for 1 hour. Cooling was started at a cooling rate of 20 ° C./hour. At the time of cooling to 320 ° C., the atmosphere with a water vapor concentration of 30 vol% was introduced into the furnace to replace the inside of the furnace, and when it was further cooled to 200 ° C., the air with a water vapor concentration of 0 vol% was again introduced into the furnace. Replaced. After cooling to 50 ° C., the photocatalytic titanium oxide powder was taken out (the process up to here is referred to as “step (II)”). When the photocatalytic activity of the photocatalytic titanium oxide obtained in the step (II) was evaluated, the carbon dioxide production rate was 7.8 μmol / hour per 1 g.
（実施例２）
実施例１の工程（Ｉ）で得られた光触媒酸化チタン粉末を炉内で水蒸気濃度０ｖｏｌ％の大気中、２００℃／時間の昇温速度で３５０℃まで昇温し、同温度を１時間保持した後、１５℃／時間の冷却速度で５０℃まで冷却した。冷却開始時に炉内に水蒸気濃度３０ｖｏｌ％の大気を導入して置換し、さらに２１０℃まで冷却した時点で、再び水蒸気濃度０ｖｏｌ％の大気を炉内に導入して置換した。５０℃まで冷却した後、光触媒酸化チタン粉末を取り出した。得られた光触媒酸化チタンの光触媒活性を評価したところ、二酸化炭素生成速度は１ｇあたり１０.５μモル／時間であった。
(Example 2)
The photocatalytic titanium oxide powder obtained in step (I) of Example 1 was heated to 350 ° C. at a heating rate of 200 ° C./hour in an atmosphere with a water vapor concentration of 0 vol% in the furnace, and the same temperature was maintained for 1 hour. Then, it was cooled to 50 ° C. at a cooling rate of 15 ° C./hour. At the start of cooling, an atmosphere with a water vapor concentration of 30 vol% was introduced into the furnace for replacement, and when it was further cooled to 210 ° C., an atmosphere with a water vapor concentration of 0 vol% was again introduced into the furnace for replacement. After cooling to 50 ° C., the photocatalytic titanium oxide powder was taken out. When the photocatalytic activity of the obtained photocatalytic titanium oxide was evaluated, the carbon dioxide production rate was 10.5 μmol / hour per gram.
（比較例１）
実施例１の工程（Ｉ）で得られた光触媒酸化チタン粉末を炉内で水蒸気濃度０ｖｏｌ％の大気中、２００℃／時間の昇温速度で３４０℃まで昇温し、同温度を１時間保持した後、炉内に水蒸気濃度５０ｖｏｌ％の大気を導入して炉内を置換し、６００℃／時間の冷却速度で３０℃まで冷却して、光触媒酸化チタン粉末を取り出した。得られた光触媒酸化チタンの光触媒活性を評価したところ、二酸化炭素生成速度は１ｇあたり４.８μモル／時間であった。
(Comparative Example 1)
The photocatalytic titanium oxide powder obtained in step (I) of Example 1 was heated in a furnace to 340 ° C. at a temperature rising rate of 200 ° C./hour in the atmosphere with a water vapor concentration of 0 vol%, and the same temperature was maintained for 1 hour. After that, an atmosphere with a water vapor concentration of 50 vol% was introduced into the furnace to replace the inside of the furnace, and the furnace was cooled to 30 ° C. at a cooling rate of 600 ° C./hour, and the photocatalytic titanium oxide powder was taken out. When the photocatalytic activity of the obtained photocatalytic titanium oxide was evaluated, the carbon dioxide production rate was 4.8 μmol / hour per gram.
Claims (6)
The method for producing highly active photocatalytic titanium oxide according to claim 4 or 5, wherein the photocatalytic titanium oxide precursor is at least one selected from the group consisting of titanium hydroxide, orthotitanic acid, metatitanic acid, and titanium nitride.
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| JP2010088964A (en) * | 2008-10-03 | 2010-04-22 | Saga Prefecture | Method for producing oxidized titanium particle |
| CN110577256A (en) * | 2019-08-21 | 2019-12-17 | 上海问鼎环保科技有限公司 | Preparation method of photocatalytic sewage treatment composite membrane |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2010088964A (en) * | 2008-10-03 | 2010-04-22 | Saga Prefecture | Method for producing oxidized titanium particle |
| CN110577256A (en) * | 2019-08-21 | 2019-12-17 | 上海问鼎环保科技有限公司 | Preparation method of photocatalytic sewage treatment composite membrane |
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