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Development of New Tantalum Base Mixed Oxide for Photocatalytic Decomposition of H_2O into H_2 and O_2

光催化分解H_2O为H_2和O_2的新型钽基混合氧化物的研制

基本信息

批准号：
13450336
负责人：
ISHIHARA Tatsumi
金额：
$ 9.6万
依托单位：
Oita University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13450336/
关键词：
Photocatalyst Dopant Effects KTaO_3 H_2O decomposition K-Ta系酸化物添加物電子濃度制御

项目摘要

Effects of electronic state of oxide semiconductor on photocatalysis of H_2O splitting into H_2 and O_2 were investigated on KTaO_3 based oxide. It was found that doping Zr, Hf, La and Ga to Ta site of KTaO_3 is highly effective for increasing the photocatalytic activity to H_2O decomposition. From the hole effects measurement, KTaO_3 is n-type semiconductor and electronic charge density decreases by doping these lower valence cations. Photo-electromotive force measurement also suggests that the life of existed hole and electron is prolonged by doping the lower valence cations. As a result, it becomes clear that the control of electronic charge density in photocatalyst is effective for increasing the photocatalytic activity to H_2O decomposition. Similar dopant effects were also observed on another compounds, i.e., SrTiO_3, Ba_2In_2O_5, and K_6Ta_<10.6>O_<30>. Effects of crystal structure was also investigated. K_2Ta_2O_6 with pyrochlore like structure and KTaO_3 with perovskite structure was successfully prepared by alkoxide method. Although the chemical composition is the same, the activity to photolysis of H2O is greatly different between K_2Ta_2O_6 and KTaO_3. This suggests that the electronic state is varied by the atomic arrangements in crystal structure and the activity to photocatalytic decomposition of water is highly affected by the electronic state of photocatalyst.

研究了氧化物半导体的电子态对KTaO_3基氧化物中H_2O分解为H_2和O_2光催化的影响。结果表明，在KTaO_3的Ta位点掺杂Zr、Hf、La和Ga可有效提高KTaO_3对H_2O分解的光催化活性。从空穴效应测量来看，KTaO_3为n型半导体，这些低价阳离子的掺杂降低了电子电荷密度。光电动势测量结果还表明，低价阳离子的掺入延长了现有空穴和电子的寿命。结果表明，控制光催化剂中的电荷密度对提高H_2O分解的光催化活性是有效的。在其他化合物SrTiO_3、Ba_2In_2O_5和K_6Ta_<10.6>O_<30>上也观察到类似的掺杂效应。研究了晶体结构的影响。采用醇氧法成功制备了具有焦绿盐结构的K_2Ta_2O_6和具有钙钛矿结构的KTaO_3。虽然化学成分相同，但K_2Ta_2O_6和KTaO_3对H2O的光解活性差异很大。这表明晶体结构中的电子态随原子排列而变化，光催化剂的电子态对水的光催化分解活性有很大影响。