JP2008006344A - Visible light-responsive photocatalyst - Google Patents
Visible light-responsive photocatalyst Download PDFInfo
- Publication number
- JP2008006344A JP2008006344A JP2006177194A JP2006177194A JP2008006344A JP 2008006344 A JP2008006344 A JP 2008006344A JP 2006177194 A JP2006177194 A JP 2006177194A JP 2006177194 A JP2006177194 A JP 2006177194A JP 2008006344 A JP2008006344 A JP 2008006344A
- Authority
- JP
- Japan
- Prior art keywords
- visible light
- photocatalyst
- photocatalytic
- materials
- activity
- 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 32
- 229910052788 barium Inorganic materials 0.000 claims abstract description 7
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 7
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 7
- 239000000203 mixture Substances 0.000 claims abstract description 7
- 229910052712 strontium Inorganic materials 0.000 claims abstract description 7
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 6
- 239000000126 substance Substances 0.000 claims description 18
- 239000004065 semiconductor Substances 0.000 claims description 15
- 239000002131 composite material Substances 0.000 claims description 8
- 238000006864 oxidative decomposition reaction Methods 0.000 claims 1
- 239000000463 material Substances 0.000 abstract description 46
- 230000001699 photocatalysis Effects 0.000 abstract description 28
- 239000010936 titanium Substances 0.000 abstract description 17
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 abstract description 16
- 229910052751 metal Inorganic materials 0.000 abstract description 15
- 239000002184 metal Substances 0.000 abstract description 15
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 abstract description 15
- 230000000694 effects Effects 0.000 abstract description 14
- 239000006104 solid solution Substances 0.000 abstract description 10
- 150000002739 metals Chemical class 0.000 abstract description 7
- 239000000243 solution Substances 0.000 abstract description 3
- 238000000034 method Methods 0.000 description 18
- 239000010955 niobium Substances 0.000 description 17
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 14
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 14
- 239000000843 powder Substances 0.000 description 9
- 238000000354 decomposition reaction Methods 0.000 description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 7
- 239000001569 carbon dioxide Substances 0.000 description 7
- 229910002092 carbon dioxide Inorganic materials 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 7
- 229910052760 oxygen Inorganic materials 0.000 description 7
- 239000001301 oxygen Substances 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- 238000010521 absorption reaction Methods 0.000 description 6
- 239000003054 catalyst Substances 0.000 description 6
- 238000013032 photocatalytic reaction Methods 0.000 description 6
- 230000007613 environmental effect Effects 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 229910052709 silver Inorganic materials 0.000 description 5
- 239000004332 silver Substances 0.000 description 5
- 238000003746 solid phase reaction Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 229910010413 TiO 2 Inorganic materials 0.000 description 4
- 238000000975 co-precipitation Methods 0.000 description 4
- 238000010304 firing Methods 0.000 description 4
- 239000005556 hormone Substances 0.000 description 4
- 229940088597 hormone Drugs 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 229910021645 metal ion Inorganic materials 0.000 description 4
- 239000012071 phase Substances 0.000 description 4
- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Chemical compound [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 description 4
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 4
- 241000894006 Bacteria Species 0.000 description 3
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 3
- 238000000862 absorption spectrum Methods 0.000 description 3
- 230000000844 anti-bacterial effect Effects 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 230000018109 developmental process Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910052758 niobium Inorganic materials 0.000 description 3
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000005416 organic matter Substances 0.000 description 3
- 230000006798 recombination Effects 0.000 description 3
- 238000005215 recombination Methods 0.000 description 3
- IGFHQQFPSIBGKE-UHFFFAOYSA-N 4-nonylphenol Chemical compound CCCCCCCCCC1=CC=C(O)C=C1 IGFHQQFPSIBGKE-UHFFFAOYSA-N 0.000 description 2
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 241000700605 Viruses Species 0.000 description 2
- 239000003463 adsorbent Substances 0.000 description 2
- 150000001299 aldehydes Chemical class 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 238000004817 gas chromatography Methods 0.000 description 2
- BDAGIHXWWSANSR-NJFSPNSNSA-N hydroxyformaldehyde Chemical compound O[14CH]=O BDAGIHXWWSANSR-NJFSPNSNSA-N 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 230000001678 irradiating effect Effects 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229910000484 niobium oxide Inorganic materials 0.000 description 2
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- 208000008842 sick building syndrome Diseases 0.000 description 2
- 229910001961 silver nitrate Inorganic materials 0.000 description 2
- 229910001923 silver oxide Inorganic materials 0.000 description 2
- 238000003980 solgel method Methods 0.000 description 2
- 229910000018 strontium carbonate Inorganic materials 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 241000195493 Cryptophyta Species 0.000 description 1
- 241000282414 Homo sapiens Species 0.000 description 1
- 229910002367 SrTiO Inorganic materials 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 244000269722 Thea sinensis Species 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000032900 absorption of visible light Effects 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000003905 agrochemical Substances 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 150000004703 alkoxides Chemical class 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 230000000840 anti-viral effect Effects 0.000 description 1
- 150000001491 aromatic compounds Chemical class 0.000 description 1
- 235000019606 astringent taste Nutrition 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000004567 concrete Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 150000002013 dioxins Chemical class 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000000383 hazardous chemical Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000001027 hydrothermal synthesis Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000002917 insecticide Substances 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 239000008204 material by function Substances 0.000 description 1
- 229910001510 metal chloride Inorganic materials 0.000 description 1
- 229910001960 metal nitrate Inorganic materials 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 229910017464 nitrogen compound Inorganic materials 0.000 description 1
- 150000002830 nitrogen compounds Chemical class 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 150000002896 organic halogen compounds Chemical class 0.000 description 1
- 150000002903 organophosphorus compounds Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 230000001443 photoexcitation Effects 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 238000011002 quantification Methods 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000000344 soap Substances 0.000 description 1
- 238000010532 solid phase synthesis reaction Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 238000000859 sublimation Methods 0.000 description 1
- 230000008022 sublimation Effects 0.000 description 1
- 150000003464 sulfur compounds Chemical class 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 239000012855 volatile organic compound Substances 0.000 description 1
Images
Abstract
Description
本発明は、可視光線の照射により物質の分解を促進させる可視光応答性光触媒に関する。
詳しくは、紫外線はもちろんのこと、太陽光、室内照明などに多く含まれる、紫外線以外
の可視光線に対しても高い光触媒活性を示すぺロブスカイト型光触媒に関する。
The present invention relates to a visible light responsive photocatalyst that promotes decomposition of a substance by irradiation with visible light.
Specifically, the present invention relates to a perovskite photocatalyst exhibiting high photocatalytic activity for visible light other than ultraviolet rays, which is contained in a lot of sunlight, indoor lighting as well as ultraviolet rays.
近年、ダイオキシン、環境ホルモンやシックハウス症候群などを引き起こすホルムアルデ
ヒドなどの有害化学物質によって、我々人類の日々の生活が脅かされつつあり、深刻な問
題となりつつある。
In recent years, the daily lives of human beings are being threatened by harmful chemical substances such as formaldehyde that cause dioxins, environmental hormones, sick house syndrome, and the like, which are becoming serious problems.
そのような有害化学物質の除去方法には活性炭などの吸着剤を利用して、有害物質を吸着
剤に吸着させて、取り除く方法もあるが、光触媒材料を利用して、有害化学物質を酸化分
解し、除去する方法も有効な方法とされ、様々な研究がなされてきている。
There is a method for removing harmful chemical substances by using an adsorbent such as activated carbon to adsorb the harmful substances to the adsorbent and removing them, but photocatalytic materials are used to oxidize and decompose the harmful chemical substances. However, the removal method is also an effective method, and various studies have been made.
現在までのところ、光触媒材料では特にアナターゼ型の酸化チタンを利用した光触媒材料
がよく利用されている。
To date, photocatalytic materials using anatase-type titanium oxide have been frequently used as photocatalytic materials.
しかしながら、酸化チタンのバンドギャップは大きいため、紫外線に対しては優れた効果
を示すが、可視光線に対しては全く機能しない。励起光源となる太陽光や蛍光灯に含まれ
ている紫外線の量は、可視光量の約４〜１０％しかなく、更なる効率のアップや室内用途
へのこれまで以上に応用していく場合、可視光に対して高活性な光触媒材料の開発が必要
とされている。それゆえ、近年、可視光領域の波長に対しても活性を示す各種光触媒材料
が提案され、さかんに研究開発がおこなわれている。
However, since the band gap of titanium oxide is large, it exhibits an excellent effect on ultraviolet rays, but does not function at all for visible light. The amount of ultraviolet light contained in sunlight and fluorescent lamps that are the excitation light source is only about 4 to 10% of the visible light amount, and when further increasing efficiency and indoor applications more than ever, There is a need to develop photocatalytic materials that are highly active against visible light. Therefore, in recent years, various photocatalytic materials that are active even at wavelengths in the visible light region have been proposed, and research and development have been conducted extensively.
たとえば、その一つに、酸化チタンにＣｒやＶなどの金属イオンをドープすることによっ
て、可視光に対しても触媒活性を発現しうる触媒が提案されている（非特許文献１）。こ
の提案によるとＣｒやＶなどの金属イオンがドープされることによって、酸化チタンの伝
導帯と価電子帯の間にエネルギー準位が新たに作り出され、その結果、バンドギャップが
狭くなり、可視光を吸収することができるようになる。しかしながら、金属イオンのドー
プによって導入されたエネルギー準位は電子とホールの再結合準位にもなりえ、活性の上
昇を期待できない場合が多い。
For example, as one of the catalysts, a catalyst that can exhibit catalytic activity even for visible light by doping titanium oxide with metal ions such as Cr and V has been proposed (Non-patent Document 1). According to this proposal, by doping metal ions such as Cr and V, a new energy level is created between the conduction band and the valence band of titanium oxide. As a result, the band gap becomes narrower and visible light is reduced. Will be able to absorb. However, the energy level introduced by doping metal ions can also be a recombination level of electrons and holes, and in many cases, an increase in activity cannot be expected.
さらに、酸化チタンに窒素などのアニオンをドープすることによって可視光応答型光触媒
材料を作製することが提案されている（特許文献１）。この提案による酸化チタン光触媒
は、金属イオンドープ型光触媒よりも確かに可視光照射下における活性は上昇するが、窒
素をドープすることによって酸化チタン内部に酸素欠陥が作製され、光触媒活性が低下し
てしまうという欠点があった。また、何れにしてもドープという手法を用いることによっ
て作製された可視光応答型光触媒材料は、現段階ではその活性はまだ不十分であり、更に
一段と高いレベルの光触媒活性を発現しうる材料が求められている。
Furthermore, it has been proposed to produce a visible light responsive photocatalytic material by doping titanium oxide with an anion such as nitrogen (Patent Document 1). The titanium oxide photocatalyst produced by this proposal certainly increases the activity under visible light irradiation than the metal ion doped photocatalyst, but doping with nitrogen creates an oxygen defect inside the titanium oxide, reducing the photocatalytic activity. There was a drawback of end. In any case, the visible light responsive photocatalyst material produced by using the dope method is still insufficient at the present stage, and there is a demand for a material that can express a higher level of photocatalytic activity. It has been.
これに対し、非ドープ型の光触媒材料は有効な材料であることが報告されている。最近
では、酸化チタン以外の酸化物を利用した可視光応答型光触媒を作製する試みもなされて
いる。たとえば、ＢｉＶＯ４は可視光照射下において硝酸銀水溶液から酸素を生成する光
触媒材料であると報告されている（非特許文献２）。しかし、この材料は有機物に対する
酸化力が不足しており、４−ノニルフェノールといった有機物を分解して二酸化炭素にま
で完全に酸化分解することができない（非特許文献３）。すなわち、価電子帯のトップの
ポテンシャルが小さすぎて、有機物を完全に酸化分解することができないことを示唆して
いる。
On the other hand, it has been reported that undoped photocatalytic materials are effective materials. Recently, an attempt has been made to produce a visible light responsive photocatalyst using an oxide other than titanium oxide. For example, BiVO 4 is reported to be a photocatalytic material that generates oxygen from an aqueous silver nitrate solution under irradiation with visible light (Non-patent Document 2). However, this material has insufficient oxidizing power for organic matter, and cannot decompose organic matter such as 4-nonylphenol and completely oxidize and decompose it to carbon dioxide (Non-patent Document 3). In other words, it suggests that the potential of the top of the valence band is too small to completely oxidize and decompose organic matter.
また、ＡｇＮｂＯ３はバンドギャップが２．８ｅＶと可視光を吸収する特性をもち、実
際、有機物を二酸化炭素にまで完全に酸化分解する特性を持つ材料である。しかし、固相
法やゾルーゲル法など、一般的に利用されている材料作製方法では結晶性が悪く、単相の
材料が作製しづらい。また、そのためか比較的比表面積が小さくなってしまう場合が多く
、可視光での光触媒活性がそれほど高くないことが報告されている（非特許文献４）。
AgNbO 3 has a band gap of 2.8 eV and absorbs visible light. In fact, AgNbO 3 is a material that completely oxidizes and decomposes organic substances to carbon dioxide. However, a generally used material manufacturing method such as a solid phase method or a sol-gel method has poor crystallinity and it is difficult to manufacture a single-phase material. For this reason, the specific surface area often becomes relatively small, and it has been reported that the photocatalytic activity in visible light is not so high (Non-patent Document 4).
さらに、Ａｇ０．０３Ｓｒ０．９７Ｔｉ０．９７Ｎｂ０．０３Ｏ３はドープされた微量
なＡｇ４ｄ軌道がＯ２ｐ軌道から構成されるバレンスバンドよりもネガチブなポテンシャ
ルにミニバンドを形成し、それゆえ、可視光に対しても吸収を示し、可視光応答型の光触
媒材料であることが報告されている（非特許文献５）。しかし、この材料ではＡｇの量が
少なすぎるため、可視光の吸収量、吸収効率が非常に低い。また、価電子帯のトップに相
当するＡｇ４ｄ軌道は酸素の２ｐ軌道と混成せず、孤立した不連続なミニバンドであるた
め、光励起により生成したホールの拡散速度が通常の半導体よりも非常におそいものと考
えられ、可視光活性の向上は望めない。
Furthermore, Ag 0.03 Sr 0.97 Ti 0.97 Nb 0.03 O 3 forms a miniband with a negative potential compared to a valence band in which a small amount of doped Ag4d orbit is composed of O2p orbitals. Therefore, it has been reported that it is also a visible light responsive photocatalytic material that absorbs visible light (Non-patent Document 5). However, since the amount of Ag is too small in this material, the amount of visible light absorbed and the absorption efficiency are very low. In addition, since the Ag4d orbit corresponding to the top of the valence band is not mixed with the 2p orbit of oxygen and is an isolated discontinuous miniband, the diffusion rate of holes generated by photoexcitation is much slower than that of a normal semiconductor. The improvement of visible light activity is not expected.
以上述べたように、近年、紫外線、可視光線の両方に対して高い活性を示す可視光応答型
光触媒の開発が期待されている。とくに入手しやすい材料による酸化物材料で、酸化チタ
ンあるいはドープ型酸化チタンあるいは既存の可視光応答型光触媒材料の触媒活性と比較
して同等以上の活性を有する材料が求められている。本発明は、この要請に応えようとい
うものである。さらに、光を照射することによって有害物質を酸化、還元、分解する、有
害物質の無害化処理、あるいは汚れの清浄化さらには抗菌特性を供する光触媒材料とこの
触媒を用いた有害物質の無害化処理方法、あるいは汚れ物質分解清浄化方法さらには抗菌
方法を提供しようと云うものである。
As described above, in recent years, development of a visible light responsive photocatalyst exhibiting high activity with respect to both ultraviolet rays and visible rays is expected. There is a demand for a material having an activity equal to or higher than the catalytic activity of titanium oxide, doped titanium oxide, or an existing visible light responsive photocatalytic material, which is an oxide material that is particularly easily available. The present invention seeks to meet this need. Furthermore, it oxidizes, reduces, and decomposes harmful substances by irradiating light, detoxifies the harmful substances, or cleans the dirt and further detoxifies the harmful substances using this catalyst and photocatalyst material that provides antibacterial properties. The present invention is intended to provide a method, a method for decomposing and cleaning dirt substances, and an antibacterial method.
上記課題を解決する為に、本発明の可視光応答性光触媒は、一般式；ＡｇｘＭ１−ｘＴｉ
1−xＮｂxＯ３（ＭはＭｇ、Ｃａ、Ｓｒ、Ｂａ、Ｚｎの１種類以上の２価の金属からなる
。また、ｘは０．０５≦ｘ＜１を示す。）で表される組成を有する複合酸化物半導体から
なることを特徴とする、構成を採用した。
In order to solve the above problems, the visible light responsive photocatalyst of the present invention has a general formula: Ag x M 1-x Ti
1-x Nb x O 3 (M is composed of one or more divalent metals of Mg, Ca, Sr, Ba, and Zn. X represents 0.05 ≦ x <1). A configuration characterized by comprising a complex oxide semiconductor having a composition was adopted.
本発明者等においては、様々な材料について鋭意研究を重ねてきた。その結果、ＡｇＮｂ
Ｏ３とＭＴｉＯ３の固溶体、ＡｇｘＭ１−ｘＴｉ1−xＮｂxＯ３（ＭはＭｇ、Ｃａ、Ｓｒ
、Ｂａ、Ｚｎの１種類以上の２価の金属からなる。また、ｘは０．０５≦ｘ ＜1を示す
。）が可視光照射下において優れた光触媒特性を持ち、可視光応答材料の１つであるＡｇ
ＮｂＯ３よりも光触媒活性が大いに向上することを見出した。これは固溶体を形成したこ
とにより、価電子帯のトップの位置を最適にすることができ、すなわち、可視光の吸収能
力を保持しながら、十分な酸化力を保持でき、また、固溶体化により反応場である表面に
到達するホールの量が増加したためであると予想される。これらの現象は単純に混ぜ合わ
せたＡｇＮｂＯ３とＭＴｉＯ３の混合物では起こりえない現象であり、固溶体化がこのよ
うなより大きな光触媒活性をもたらすキーポイントであるといえる。
また、これらの材料はドーピング材料に比べて欠陥も少なく、再結合もおきづらい光触媒
材料であると考えられる。さらにＸ＝０．０５以上ＡｇＮｂＯ３をＭＴｉＯ３と固溶させ
ることで、価電子帯のトップの位置がＡｇ４ｄ軌道とＯ２ｐ軌道がハイブリットし、すな
わち、ポテンシャルで考えた場合、Ａｇ４ｄ軌道とＯ２ｐ軌道が連続しているという長所
を持つのに対し、ミニバンドを形成したＡｇ０．０３Ｓｒ０．９７Ｔｉ０．９７Ｎｂ０．
０３Ｏ３ではＡｇ４ｄ軌道と０２ｐ軌道が不連続であり、価電子帯のトップの位置はＡｇ
４ｄのみである。
それゆえ、生成したホールの移動度に大きな差異が生まれる。
生成したホールの移動度はミニバンドを形成したＡｇ０．０３Ｓｒ０．９７Ｔｉ０．９７
Ｎｂ０．０３Ｏ３と比べて、本発明の材料は格段に向上しているものと考えられる。
なお、この生成したホールの表面への拡散速度は光触媒反応の律速因子の１つであること
が知られている。本発明は、この知見に基づいてなされたものである。
The inventors have conducted extensive research on various materials. As a result, AgNb
A solid solution of O 3 and MTiO 3 , Ag x M 1-x Ti 1-x Nb x O 3 (M is Mg, Ca, Sr
It consists of one or more divalent metals of Ba, Zn. X represents 0.05 ≦ x <1. ) Has excellent photocatalytic properties under visible light irradiation and is one of visible light responsive materials.
It has been found that the photocatalytic activity is greatly improved over NbO 3 . By forming a solid solution, the top position of the valence band can be optimized, that is, sufficient oxidizing power can be maintained while maintaining the ability to absorb visible light, and the reaction can be achieved by solid solution. This is probably because the amount of holes reaching the surface of the field has increased. These phenomena cannot occur in a mixture of AgNbO 3 and MTiO 3 simply mixed, and it can be said that solid solution formation is a key point that brings such a larger photocatalytic activity.
In addition, these materials are considered to be photocatalytic materials with fewer defects and less recombination than doping materials. By further solid solution and MTiO 3 a X = 0.05 or more AgNbO 3, the top position of the valence band and the hybrid is Ag4d trajectory and O2p track, i.e., when considered in potential, is Ag4d orbital and O2p track Ag 0.03 Sr 0.97 Ti 0.97 Nb in which a mini-band is formed while having the advantage of being continuous .
In 03 O 3 , the Ag4d orbit and 02p orbit are discontinuous, and the top position of the valence band is Ag.
Only 4d.
Therefore, there is a big difference in the mobility of generated holes.
The mobility of the generated hole was Ag 0.03 Sr 0.97 Ti 0.97 forming a miniband.
Compared with Nb 0.03 O 3 , it is considered that the material of the present invention is remarkably improved.
It is known that the diffusion rate of the generated holes to the surface is one of the rate limiting factors of the photocatalytic reaction. The present invention has been made based on this finding.
本発明は、銀と２価の金属元素、ニオブ、チタン、酸素からなる複合酸化物半導体光触媒
であって、光を照射すると可視光領域の波長のスペクトルを十分に吸収し、光触媒反応を
おこすことができる。この点においてこれまで実用化されてきた酸化チタンをベースとし
た紫外光応答型光触媒に比して、極めて高い優位性を持つ材料である。
また、ＣｒやＮをドープした材料に比べても、欠陥量が少なく、電子とホールの再結合も
起こりづらく、光触媒活性も高い。本発明によれば、紫外光のみならず、可視光を利用し
て、工場などで最もよく利用されているＶＯＣの１種、２−プロピルアルコール（ＩＰＡ
）を効率よく分解できる格別の効果を有しているものである。
この光触媒の特性はこれだけにとどまらず、光を照射することによってその他の有害ガス
、たとえば、シックハウス症候群の原因ガスの１つであるアルデヒドガスや環境ホルモン
などの様々な有害物質を分解、除去することができる能力を有している。
また、ウィルスや細菌に対しても抗ウィルス、抗菌効果を期待できる。
本発明の可視光応答性光触媒は、可視光、紫外光領域に対して活性を有することは上記の
通りであり、その特性の故、前示した使用例以外にも多様な用途に利用できることが期待
され、今後その果たす役割は、非常に大きいものと考えられる。
The present invention is a composite oxide semiconductor photocatalyst composed of silver and a divalent metal element, niobium, titanium, and oxygen. When irradiated with light, the photocatalytic reaction is caused by sufficiently absorbing the wavelength spectrum in the visible light region. Can do. In this respect, it is a material having an extremely high advantage compared with the ultraviolet light-responsive photocatalyst based on titanium oxide that has been put into practical use so far.
Also, compared to materials doped with Cr or N, the amount of defects is small, recombination of electrons and holes hardly occurs, and photocatalytic activity is high. According to the present invention, not only ultraviolet light but also visible light, one of the VOCs most often used in factories, 2-propyl alcohol (IPA)
) Can be decomposed efficiently.
This photocatalyst is not limited to this, but it also decomposes and removes other harmful gases such as aldehyde gas and environmental hormones that are one of the cause gases of sick house syndrome by irradiating light. Has the ability to
Antiviral and antibacterial effects can also be expected against viruses and bacteria.
As described above, the visible light responsive photocatalyst of the present invention has activity in the visible light and ultraviolet light regions, and because of its characteristics, it can be used for various applications other than the use examples shown above. Expected and expected to play a very important role in the future.
本発明の光触媒としての複合酸化物半導体を得るためには、通常の固相反応法、すなわち
原料となる各金属成分の酸化物あるいは金属炭酸塩あるいは金属硝酸塩あるいは金属硫酸
塩、あるいは金属塩化物を目的組成の比率で混合し、常圧下空気中で焼成することによっ
て合成することができる。
また、焼成の際、原料成分によっては、昇華し、触媒の材料設計に、計画された設計とは
ズレが生ずることもあるが、この場合、昇華に見合う量を最初から多めに加えておくこと
によって対処することができる。
また、上記原料以外に金属アルコキシドや金属塩を原料とし、これをいわゆるゾルーゲル
法、共沈法、錯体重合法、スパッタリング法、化学蒸着法、水熱合成法などといった様々
な方法によって調製することができ、何れの調製プロセスによっても実施可能である。
調整された配合原料を焼成する際の焼成温度は、原料物質が分解して酸化物に転換され、
酸化物からなる焼結体が得られる温度であればよい。
In order to obtain a composite oxide semiconductor as a photocatalyst of the present invention, an ordinary solid phase reaction method, that is, an oxide, metal carbonate, metal nitrate, metal sulfate, or metal chloride of each metal component as a raw material is used. It can synthesize | combine by mixing by the ratio of the target composition and baking in air under normal pressure.
Also, depending on the raw material components during firing, the material design of the catalyst may deviate from the planned design, but in this case, add an amount appropriate for sublimation from the beginning. Can be dealt with by.
In addition to the above raw materials, a metal alkoxide or a metal salt can be used as a raw material, which can be prepared by various methods such as so-called sol-gel method, coprecipitation method, complex polymerization method, sputtering method, chemical vapor deposition method, hydrothermal synthesis method and the like. It can be carried out by any preparation process.
The firing temperature when firing the adjusted blended raw material is converted into an oxide by decomposition of the raw material,
Any temperature may be used as long as a sintered body made of an oxide is obtained.
本発明の光触媒に用いる複合酸化物半導体の形状、粒径は、光を有効に利用するためにで
きるだけ表面積が大きくなるように設計されることが望ましい。
固相反応法によって作製した複合酸化物半導体は、大きな成型物あるいは塊状物として得
られるため、これをボールミルなどで粉砕するか、あるいは酸などでエッチングすること
によってさらに表面積を大きくすることができる。
また、メソポーラス構造になるように合成して、表面積を大きくしてもよいし、高い表面
積を持つ担体に担持してもよい。
さらに、粉末粒子を適宜大きさの形状、形態に成形して使用することもできる。本発明の
光触媒に用いる複合酸化物半導体は、焼結法以外にも、前述記載した様々な調整手段が利
用でき、たとえば、触媒成分を含む水溶液等の反応原料溶液を用意し、反応溶液から共析
反応、あるいは共沈反応によって、触媒成分を含む物質を共析、共沈させ、それらをさら
に乾燥脱水あるいは焼成することによっても作製することができる。
The shape and particle size of the composite oxide semiconductor used for the photocatalyst of the present invention are desirably designed so that the surface area becomes as large as possible in order to effectively use light.
Since the complex oxide semiconductor manufactured by the solid phase reaction method is obtained as a large molded product or lump, the surface area can be further increased by pulverizing it with a ball mill or etching with an acid or the like.
Further, the surface area may be increased by synthesizing so as to have a mesoporous structure, or may be supported on a carrier having a high surface area.
Furthermore, it is possible to use the powder particles by appropriately shaping them into a shape and shape. The composite oxide semiconductor used for the photocatalyst of the present invention can use the various adjusting means described above in addition to the sintering method. For example, a reaction raw material solution such as an aqueous solution containing a catalyst component is prepared, It can also be produced by co-precipitation and co-precipitation of a substance containing a catalyst component by precipitation reaction or co-precipitation reaction, and further drying and dehydrating or baking them.
本発明の光触媒材料の電荷分離を促進し、光触媒反応を加速させるためにＰｔやＰｄ、Ａ
ｇなどの貴金属を数％以下程度、複合酸化物半導体に担持させてもよい。
In order to accelerate the charge separation of the photocatalytic material of the present invention and accelerate the photocatalytic reaction, Pt, Pd, A
A noble metal such as g may be supported on the composite oxide semiconductor to a few percent or less.
本発明の光触媒による光触媒反応により分解あるいは酸化あるいは還元反応により除去で
きる有害物質としては、環境ホルモン、農薬、殺虫剤、カビ、細菌、ウィルス、藻類、環
境汚染物質、フロンガス、炭化水素、アルコール、アルデヒド、ケトン、カルボン酸、一
酸化炭素、アミン、油、芳香族化合物、有機ハロゲン化合物、窒素化合物、硫黄化合物、
有機リン化合物、蛋白質などが挙げられる。さらに身の回りの汚れの原因となっている石
鹸かすや油、手垢、茶渋、台所のシンクなどのぬめりなどが例示できる。
Hazardous substances that can be decomposed or removed by oxidation or reduction reaction by the photocatalytic reaction of the photocatalyst of the present invention include environmental hormones, agricultural chemicals, insecticides, molds, bacteria, viruses, algae, environmental pollutants, chlorofluorocarbons, hydrocarbons, alcohols, aldehydes , Ketone, carboxylic acid, carbon monoxide, amine, oil, aromatic compound, organic halogen compound, nitrogen compound, sulfur compound,
Examples include organophosphorus compounds and proteins. Furthermore, examples include soap scum and oil, dirt, tea astringency, and kitchen sinks that cause personal contamination.
以下、本発明を具体的な実施例と図面に基づいて詳細に説明するが、これらは本発明を限
定するものではない。以下の実施例においては、一般式；ＡｇｘＭ１−ｘＴｉ1−xＮｂx
Ｏ３（ＭはＭｇ、Ｃａ、Ｓｒ、Ｂａ、Ｚｎの１種類以上の２価の金属からなる。また、ｘ
は０．０５ ≦ ｘ < 1を示す。）で示される複合酸化物半導体よりなる光触媒を実施
例として、固相反応法で合成した例を示す。
Hereinafter, although the present invention is explained in detail based on a concrete example and a drawing, these do not limit the present invention. In the following examples, the general formula: Ag x M 1-x Ti 1-x Nb x
O 3 (M is made of one or more divalent metals such as Mg, Ca, Sr, Ba, and Zn. In addition, x
Indicates 0.05 ≦ x <1. As an example, a photocatalyst composed of a complex oxide semiconductor represented by the following formula) is synthesized by a solid phase reaction method.
実施例１；
先ず、酸化銀、酸化ニオブ、炭酸ストロンチウム、酸化チタンを組成比どおり秤量し、ボ
ールミルや乳鉢などの粉砕混合器具を利用して十分に粉砕混合した。
その後、アルミナるつぼに入れて、大気圧空気雰囲気下で１０００℃にて２４時間焼結し
、粉末を得た。
また、必要ならば空気雰囲気に変えて酸素雰囲気で焼成をおこなってもよい。
この粉末をＸ線回折装置を用いて、測定したところ（図１）、ｘの変化に伴い、回折ピー
クが一方向にシフトし、結晶構造が系統的に変化していることが判明した。
また、銀以外の不純物相は確認されず、ＡｇｘＳｒ１−ｘＴｉ1−xＮｂxＯ３の（ｘ＝０
．０５、０．５、０．７５）の固溶体が得られていることがわかった。
また、吸収スペクトルの測定から上記の固溶体は可視光に対して吸収を持つことがわかっ
た（図２）。特にｘ＝０．５とｘ＝０．７５の材料においては吸収端が明らかにｘ＝０で
可視光を吸収しないＳｒＴｉＯ３と比べてレッドシフトしており、これらの固溶体材料に
おける可視光の吸収は孤立した不連続なＡｇ４ｄミニバンドと伝導帯のボトム間による吸
収ではなく、Ａｇ４ｄ＋Ｏ２ｐ混成軌道と伝導帯のボトム間に由来する吸収であると言え
る（図３）。
Example 1;
First, silver oxide, niobium oxide, strontium carbonate, and titanium oxide were weighed according to the composition ratio and sufficiently pulverized and mixed using a pulverizing and mixing device such as a ball mill or a mortar.
Thereafter, the mixture was put in an alumina crucible and sintered at 1000 ° C. for 24 hours in an atmospheric air atmosphere to obtain a powder.
Further, if necessary, firing may be performed in an oxygen atmosphere instead of an air atmosphere.
When this powder was measured using an X-ray diffractometer (FIG. 1), it was found that the diffraction peak shifted in one direction with the change of x, and the crystal structure was systematically changed.
Further, no impurity phase other than silver was confirmed, and Ag x Sr 1-x Ti 1-x Nb x O 3 (x = 0
. 05, 0.5, 0.75) was found to be obtained.
Moreover, it turned out that said solid solution has absorption with respect to visible light from the measurement of an absorption spectrum (FIG. 2). In particular, in the materials of x = 0.5 and x = 0.75, the absorption edge is clearly red-shifted compared to SrTiO 3 which does not absorb visible light at x = 0, and the absorption of visible light in these solid solution materials. Is not absorption between the isolated discrete Ag4d miniband and the bottom of the conduction band, but absorption derived from the Ag4d + O2p hybrid orbit and the bottom of the conduction band (FIG. 3).
Ａｇ０．５Ｓｒ０．５Ｔｉ０．５Ｎｂ０．５Ｏ３の紫外−可視吸収スペクトル測定の結果
は、紫外線領域から約４５０ｎｍ程度までの可視光領域まで吸収を示した（図２）。
この半導体を比表面積が約１〜２ｍ２ｇ−１程度の粉体にして、濃度３ｇＬ−１の硝酸
銀水溶液０．２７リットルに０．５ｇ混入、懸濁させて、その分解試験を行った。
光源には３００Ｗ Ｘｅランプを用い、カットオフフィルターを利用して、４００ｎｍ以
上の可視光を反応容器に照射した。生成した酸素の定量はガスクロマトグラフィー（検出
器はＴＣＤ）で行った。
その結果、酸素は１時間で約１２０μモル生成することが確認された。以上のことからこ
の材料は可視光応答型の光触媒であることがわかった。
The result of ultraviolet-visible absorption spectrum measurement of Ag 0.5 Sr 0.5 Ti 0.5 Nb 0.5 O 3 showed absorption from the ultraviolet region to the visible light region from about 450 nm (FIG. 2).
This semiconductor was made into a powder having a specific surface area of about 1-2 m 2 g −1 , mixed and suspended in 0.27 liter of a silver nitrate aqueous solution having a concentration of 3 g L −1 , and a decomposition test was conducted.
A 300 W Xe lamp was used as a light source, and a visible light of 400 nm or more was irradiated to the reaction vessel using a cut-off filter. The produced oxygen was quantified by gas chromatography (detector was TCD).
As a result, it was confirmed that about 120 μmol of oxygen was generated in 1 hour. From the above, it was found that this material is a visible light responsive photocatalyst.
実施例２；
ＡｇｘＭ１−ｘＴｉ1−xＮｂxＯ３複合酸化物半導体の１つであるＡｇ−Ａｇ０．７５Ｓ
ｒ０．２５Ｔｉ０．２５Ｎｂ０．７５Ｏ３を以下に述べるように固相反応法によって合成
した。
先ず、酸化銀を０．５８２ｇと酸化ニオブ０．４００ｇ、炭酸ストロンチウムを０．１６
２ｇ、酸化チタン０．０８７７ｇをそれぞれ秤量した。
実施例１と同様に、これらを十分に粉砕混合したあと大気圧空気雰囲気下で１０００℃に
て２４時間焼結し、粉末を得た。この粉末をＸ線回折装置を用いて、測定したところ、銀
以外の不純物相は確認されず、Ａｇ０．７５Ｓｒ０．２５Ｔｉ０．２５Ｎｂ０．７５Ｏ３
の固溶体が得られていることがわかった。
Example 2;
Ag x M 1-x Ti 1 -x
r 0.25 Ti 0.25 Nb 0.75 O 3 was synthesized by the solid phase reaction method as described below.
First, 0.582 g of silver oxide, 0.400 g of niobium oxide, and 0.16 of strontium carbonate.
2 g and 0.0877 g of titanium oxide were weighed.
In the same manner as in Example 1, these were sufficiently pulverized and mixed, and then sintered at 1000 ° C. for 24 hours in an atmospheric air atmosphere to obtain a powder. When this powder was measured using an X-ray diffractometer, no impurity phase other than silver was confirmed, and Ag 0.75 Sr 0.25 Ti 0.25 Nb 0.75 O 3.
It was found that a solid solution was obtained.
本実施例で得られたＡｇ−Ａｇ０．７５Ｓｒ０．２５Ｔｉ０．２５Ｎｂ０．７５Ｏ３の比
表面積が１〜２ｍ２ｇ−１程度になる粉末０．４ｇを０．５リットルの反応容器に入れて
、２−プロピルアルコール（約１６０ｐｐｍ）ガスの分解試験を行った。
光源には３００Ｗ Ｘｅランプを用い、カットオフフィルターを利用して、４００ｎｍか
ら５２０ｎｍの可視光（光量：１．６ｍＷｃｍ−２）を反応容器に照射した。
２−プロピルアルコールと二酸化炭素の検出及び定量はメタナイザー付ガスクロマトグラ
フィー（検出器はＦＩＤ）で行い、最終生成物、二酸化炭素の発生量についても併せて調
査した（図４）。
その結果、光照射後、１時間で２−プロピルアルコールが約１３０ｐｐｍ分解し、その後
、さらに光照射を続けたところ、約１日、光照射することで二酸化炭素濃度は約２４０ｐ
ｐｍに達した。これは最初に投入した２−プロピルアルコールのほぼ半分量、二酸化炭素
にまで全分解したことを意味する。
この材料の比表面積は１〜２ｍ２ｇ−１であるため、分解に時間を要するが、担体の利用
や微粒子化によって、比表面積を広げることにより、その分解時間が大幅に短縮されるこ
とは容易に予測できる。以上のことから、この材料が可視光において光触媒特性を示すこ
とは明らかであり、新規の有望な可視光応答型の光触媒材料であるといえる。
0.5 liters of 0.4 g of the powder obtained in this example in which the specific surface area of Ag—Ag 0.75 Sr 0.25 Ti 0.25 Nb 0.75 O 3 is about 1 to 2 m 2 g −1 The decomposition test of 2-propyl alcohol (about 160 ppm) gas was conducted.
A 300 W Xe lamp was used as the light source, and the reaction vessel was irradiated with visible light (light amount: 1.6 mWcm −2 ) from 400 nm to 520 nm using a cutoff filter.
The detection and quantification of 2-propyl alcohol and carbon dioxide were performed by gas chromatography with a methanizer (detector was FID), and the final product and the amount of carbon dioxide generated were also investigated (FIG. 4).
As a result, about 130 ppm of 2-propyl alcohol decomposes in one hour after the light irradiation, and then the light irradiation is continued. The carbon dioxide concentration is about 240 p by light irradiation for about one day.
Reached pm. This means that almost half the amount of 2-propyl alcohol charged first was completely decomposed to carbon dioxide.
Since the specific surface area of this material is 1 to 2 m 2 g −1, it takes time to decompose, but the decomposition time can be greatly shortened by expanding the specific surface area by using a carrier or making fine particles. Easy to predict. From the above, it is clear that this material exhibits photocatalytic properties in visible light, and it can be said that this material is a new and promising visible light responsive photocatalytic material.
比較例１；
代表的な光触媒であるアナターゼ型ＴｉＯ２を利用して２−プロピルアルコール分解の可
視光分解活性を調べた。この粉末の比表面積は約８ｍ２ｇ−１である。測定に使用した機
器は実施例２と同じであった。その結果、１時間経過しても中間体のアセトン、二酸化炭
素の生成量はなく、気相中の２−プロピルアルコールの量に変化もないことから２−プロ
ピルアルコールは、全く分解されないことが確認された。紫外光において優れた活性を示
すＴｉＯ２も可視光照射においては活性を示さず、可視光領域における光触媒活性はＡｇ
ｘＭ１−ｘＴｉ1−xＮｂxＯ３（ＭはＭｇ、Ｃａ、Ｓｒ、Ｂａ、Ｚｎの１種類以上の２価
の金属からなる。また、ｘは０．０５≦ｘ＜1を示す。）よりも著しく劣っていた。以上
のことから、このＴｉＯ２光触媒は、可視光照射下においては２−プロピルアルコールを
はじめとする有機物を分解する能力がないことが再確認された（図４）。
Comparative Example 1;
The visible light decomposition activity of 2-propyl alcohol decomposition was investigated using anatase TiO 2 which is a typical photocatalyst. The specific surface area of this powder is about 8 m 2 g −1 . The equipment used for the measurement was the same as in Example 2. As a result, it was confirmed that 2-propyl alcohol was not decomposed at all because there was no production of intermediate acetone and carbon dioxide even after 1 hour, and there was no change in the amount of 2-propyl alcohol in the gas phase. It was done. TiO 2 which shows excellent activity in ultraviolet light also shows no activity in visible light irradiation, and the photocatalytic activity in the visible light region is Ag.
x M 1-x Ti 1- x Nb x O 3 (M is Mg, Ca, Sr, Ba, consisting of one or more divalent metals Zn. Further, x is shows a 0.05 ≦ x <1 )). From the above, it was reconfirmed that this TiO 2 photocatalyst has no ability to decompose organic substances such as 2-propyl alcohol under visible light irradiation (FIG. 4).
比較例２；
代表的な可視光応答型光触媒であるＡｇＮｂＯ３の粉末を利用して２−プロピルアルコー
ルの可視光分解活性を調べた。ＡｇＮｂＯ３は実施例１、２と同じように固相反応法によ
り合成し、同様な比表面積を有した。また、測定に使用した機器は実施例２と同じであっ
た。その結果、１時間で２−プロパノールが約２０ｐｐｍ分解することが確認された。実
施例２と比較した場合、ＡｇＮｂＯ３の光触媒活性は明らかに劣っていることがわかった
。このように銀、２価の金属、ニオブ、チタンからなる複合酸化物固溶体半導体は既存の
可視光応答型材料よりも格段に高い活性を持っており、非常に有効な可視光応答型の光触
媒材料であることがわかる（図４）。
Comparative Example 2;
The visible light decomposition activity of 2-propyl alcohol was examined using powder of AgNbO 3 which is a typical visible light responsive photocatalyst. AgNbO 3 was synthesized by the solid phase reaction method in the same manner as in Examples 1 and 2, and had the same specific surface area. The equipment used for the measurement was the same as in Example 2. As a result, it was confirmed that 2-propanol decomposes about 20 ppm in one hour. When compared with Example 2, it was found that the photocatalytic activity of AgNbO 3 was clearly inferior. Thus, the composite oxide solid solution semiconductor composed of silver, divalent metal, niobium, and titanium has much higher activity than existing visible light responsive materials, and is a very effective visible light responsive photocatalyst material. (FIG. 4).
以上の結果について、図１―４に示していることは、前述したとおりである。
すなわち、銀、２価の金属、ニオブからなる複合酸化物半導体は高活性な可視光応答型光
触媒材料であり、前述の目的に沿う材料の開発に成功したことを示している。これによっ
て、照射される光の波長に対して、利用効率が高まり、光触媒反応に一層有効に利用され
、寄与するものと期待される。
The above results are shown in FIGS. 1-4 as described above.
That is, a composite oxide semiconductor composed of silver, a divalent metal, and niobium is a highly active visible light responsive photocatalytic material, indicating that the material that meets the above-mentioned purpose has been successfully developed. As a result, the use efficiency is increased with respect to the wavelength of the irradiated light, and it is expected to be more effectively utilized and contribute to the photocatalytic reaction.
以上説明してきたように、本発明は、一般式；ＡｇｘＭ１−ｘＴｉ1−xＮｂxＯ３（Ｍは
Ｍｇ、Ｃａ、Ｓｒ、Ｂａ、Ｚｎの１種類以上の２価の金属からなる。また、ｘは０．０５
≦ｘ＜１を示す。）複合酸化物半導体よりなる光触媒は、紫外光のみならず、十分に可視
光まで吸収できる。
本発明によって、これまでの実用光触媒、ＴｉＯ２が、紫外光領域でのみ機能していたこ
とを考えると、有効利用できる波長領域を大きく広げることができたという意義は極めて
大きい。また、可視光領域においても既存のＡｇＮｂＯ３よりも活性が格段に高い。本発
明によれば、可視光を利用して各種有害な化合物、例えば、環境ホルモンや細菌等いわゆ
る有害物質に作用し、これらを殺菌、分解、除去等無害化するのに使用される環境対策技
術を始めとして各種化学反応に大いに利用され、産業の発展に寄与するものと期待される
。
As described above, the present invention has the general formula: Ag x M 1-x Ti 1-x Nb x O 3 (M is one or more divalent metals of Mg, Ca, Sr, Ba, Zn). X is 0.05.
<= X <1 is shown. ) A photocatalyst made of a complex oxide semiconductor can absorb not only ultraviolet light but also visible light.
Considering that the present practical photocatalyst, TiO 2 , functioned only in the ultraviolet light region according to the present invention, it is extremely significant that the wavelength region that can be effectively used can be greatly expanded. In the visible light region, the activity is much higher than that of existing AgNbO 3 . According to the present invention, environmental countermeasure technology used to make various harmful compounds using visible light, such as environmental hormones and bacteria, so-called harmful substances, sterilize, decompose, remove, etc. It is expected to contribute to the development of industry by being used for various chemical reactions.
Claims (1)
式；ＡｇｘＭ１−ｘＴｉ1−xＮｂxＯ３（ＭはＭｇ、Ｃａ、Ｓｒ、Ｂａ、Ｚｎの１種類以
上の２価の金属からなる。また、ｘは０．０５≦ｘ＜1を示す。）で表される組成を有す
る複合酸化物半導体からなることを特徴とする、可視光応答性光触媒。
A visible light responsive photocatalyst that promotes oxidative decomposition of a substance by irradiation with visible light, and has a general formula: Ag x M 1-x Ti 1-x Nb x O 3 (M is Mg, Ca, Sr, Ba, Zn) And a composite oxide semiconductor having a composition represented by the following formula: x is 0.05 ≦ x <1. photocatalyst.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006177194A JP4997627B2 (en) | 2006-06-27 | 2006-06-27 | Visible light responsive photocatalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006177194A JP4997627B2 (en) | 2006-06-27 | 2006-06-27 | Visible light responsive photocatalyst |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2008006344A true JP2008006344A (en) | 2008-01-17 |
| JP4997627B2 JP4997627B2 (en) | 2012-08-08 |
Family
ID=39065046
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2006177194A Expired - Fee Related JP4997627B2 (en) | 2006-06-27 | 2006-06-27 | Visible light responsive photocatalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4997627B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012173400A2 (en) * | 2011-06-15 | 2012-12-20 | Samsung Electronics Co., Ltd. | Visible light sensitive photocatalyst, method of producing the same, and electrochemical water decomposition cell, water decomposition system, and organic material decomposition system each including the same |
| KR20120138646A (en) * | 2011-06-15 | 2012-12-26 | 삼성전자주식회사 | Visible light sensitive photocatalyst, method of producing the same, electrochemical water splitting cell, water splitting system, organic material decomposition system comprising the same |
| CN103316660A (en) * | 2013-06-25 | 2013-09-25 | 桂林理工大学 | Visible-light-responded photocatalyst Ba2Ti3Nb4O18 and preparation method thereof |
| CN109317133A (en) * | 2018-10-30 | 2019-02-12 | 黄冈师范学院 | A kind of microwave synthesis method of niobium pentaoxide/nano titania compound photochemical catalyst |
| CN109650884A (en) * | 2018-09-09 | 2019-04-19 | 中南大学 | A kind of niobic acid silver based cermets and its preparation method and application |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1192176A (en) * | 1997-07-22 | 1999-04-06 | Bridgestone Corp | Photocatalytic film and its production |
| JP2000237598A (en) * | 1999-02-23 | 2000-09-05 | Kansai Research Institute | Production of visible ray response type photocatalyst |
| JP2002226926A (en) * | 2001-02-02 | 2002-08-14 | Japan Science & Technology Corp | Composite functional material and its manufacturing method |
| JP2002255502A (en) * | 2001-02-26 | 2002-09-11 | National Institute Of Advanced Industrial & Technology | Light energy conversion by iodine compound and semiconductor photocatalyst |
-
2006
- 2006-06-27 JP JP2006177194A patent/JP4997627B2/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1192176A (en) * | 1997-07-22 | 1999-04-06 | Bridgestone Corp | Photocatalytic film and its production |
| JP2000237598A (en) * | 1999-02-23 | 2000-09-05 | Kansai Research Institute | Production of visible ray response type photocatalyst |
| JP2002226926A (en) * | 2001-02-02 | 2002-08-14 | Japan Science & Technology Corp | Composite functional material and its manufacturing method |
| JP2002255502A (en) * | 2001-02-26 | 2002-09-11 | National Institute Of Advanced Industrial & Technology | Light energy conversion by iodine compound and semiconductor photocatalyst |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012173400A2 (en) * | 2011-06-15 | 2012-12-20 | Samsung Electronics Co., Ltd. | Visible light sensitive photocatalyst, method of producing the same, and electrochemical water decomposition cell, water decomposition system, and organic material decomposition system each including the same |
| KR20120138646A (en) * | 2011-06-15 | 2012-12-26 | 삼성전자주식회사 | Visible light sensitive photocatalyst, method of producing the same, electrochemical water splitting cell, water splitting system, organic material decomposition system comprising the same |
| WO2012173400A3 (en) * | 2011-06-15 | 2013-04-04 | Samsung Electronics Co., Ltd. | Visible light sensitive photocatalyst, method of producing the same, and electrochemical water decomposition cell, water decomposition system, and organic material decomposition system each including the same |
| US9718695B2 (en) | 2011-06-15 | 2017-08-01 | Samsung Electronics Co., Ltd. | Visible light sensitive photocatalyst, method of producing the same, and electrochemical water decomposition cell, water decomposition system, and organic material decomposition system each including the same |
| KR101968643B1 (en) | 2011-06-15 | 2019-04-12 | 삼성전자주식회사 | Visible light sensitive photocatalyst, method of producing the same, electrochemical water splitting cell, water splitting system, organic material decomposition system comprising the same |
| CN103316660A (en) * | 2013-06-25 | 2013-09-25 | 桂林理工大学 | Visible-light-responded photocatalyst Ba2Ti3Nb4O18 and preparation method thereof |
| CN109650884A (en) * | 2018-09-09 | 2019-04-19 | 中南大学 | A kind of niobic acid silver based cermets and its preparation method and application |
| CN109650884B (en) * | 2018-09-09 | 2021-10-15 | 中南大学 | Silver niobate-based ceramic and preparation method and application thereof |
| CN109317133A (en) * | 2018-10-30 | 2019-02-12 | 黄冈师范学院 | A kind of microwave synthesis method of niobium pentaoxide/nano titania compound photochemical catalyst |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4997627B2 (en) | 2012-08-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Jin et al. | Improved photocatalytic NO removal activity of SrTiO3 by using SrCO3 as a new co-catalyst | |
| Liu et al. | Removing surface hydroxyl groups of Ce-modified MnO2 to significantly improve its stability for gaseous ozone decomposition | |
| KR100945035B1 (en) | Tungstates based visible-light induced oxides photocatalysts and synthesis methods thereof | |
| Zaleska | Doped-TiO2: a review | |
| Sofianou et al. | Tuning the photocatalytic selectivity of TiO2 anatase nanoplates by altering the exposed crystal facets content | |
| Xie et al. | Enhanced photocatalytic degradation of RhB driven by visible light-induced MMCT of Ti (IV)− O− Fe (II) formed in Fe-doped SrTiO3 | |
| TWI476043B (en) | Photocatalytic materials and process for producing the same | |
| JP2007216223A (en) | Photocatalytic material having semiconductor properties, and its manufacturing method and use | |
| JP2009078211A (en) | Photocatalyst | |
| WO2006064799A1 (en) | Composite metal oxide photocatalyst exhibiting responsibility to visible light | |
| Li et al. | Oxygen vacancies-modified S-scheme Bi2Ti2O7/CaTiO3 heterojunction for highly efficient photocatalytic NO removal under visible light | |
| Colón et al. | Effect of ZrO2 incorporation and calcination temperature on the photocatalytic activity of commercial TiO2 for salicylic acid and Cr (VI) photodegradation | |
| KR101146899B1 (en) | Photocatalyst having titanium dioxide and a metal tungsten oxide junction structure and preparation method thereof | |
| US20170072391A1 (en) | Photocatalytic hydrogen production from water over mixed phase titanium dioxide nanoparticles | |
| Golestanbagh et al. | Preparation, characterization and photocatalytic properties of visible-light-driven CuO/SnO 2/TiO 2 photocatalyst | |
| Mohamed et al. | Mesoporous BiVO4/2D-g-C3N4 heterostructures for superior visible light-driven photocatalytic reduction of Hg (II) ions | |
| JP4997627B2 (en) | Visible light responsive photocatalyst | |
| JP2004160327A (en) | MOx-ZnO COMPOSITE ZINC OXIDE PHOTOCATALYST AND PRODUCTION METHOD THEREFOR | |
| Tai et al. | Nano-photocatalyst in photocatalytic oxidation processes | |
| JP3742873B2 (en) | Photocatalyst, method for producing hydrogen using the same, and method for decomposing toxic substances | |
| WO2005087371A1 (en) | Photocatalyst based on composite oxide responsive to visible light and method for decomposition and removal of harmful chemical material using the same | |
| Ordoñez et al. | One-pot synthesis of Ag-modified SrTiO3: synergistic effect of decoration and doping for highly efficient photocatalytic NOx degradation under LED | |
| Raciulete et al. | Particularities of trichloroethylene photocatalytic degradation over crystalline RbLaTa2O7 nanowire bundles grown by solid-state synthesis route | |
| KR20070028102A (en) | Preparation method of nano size copper-manganese complex oxide catalyst and the catalyst prepared by the method | |
| JP2008006328A (en) | Photocatalyst comprising visible light responsive composite oxide semiconductor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20090622 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20110425 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20120131 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20120308 |
|
| 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: 20120424 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20120427 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20150525 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20150525 Year of fee payment: 3 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |