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High efficient charges separation-type photo-electrode with controlled energy band-bending

可控能带弯曲的高效电荷分离型光电极

基本信息

批准号：
16206075
负责人：
MATSUO Shinya
金额：
$ 32.45万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

An energy band-bending induced by homo-and hetero-junctions of semiconductors must be a key factor for attainment of efficient hydrogen production via photo-electrode water splitting. In the present study, composites of TiO_2 with donor-doped titanate, Sr(Ti_<1x>Nb_x)O_<3+5> in states of powder, single crystal and thin film, were prepared, and various pysico-chemical phenomena, i.e., photo-bleaching of dyes, water splitting photo-reaction, dye-sensitized photo-current, and ions adsorption, were investigated. (1) Photobleaching of methylene blue aqueous solution sensitized with Sr(Ti_<1-x>Nb_x)O_<3+δ>/ TiO_2 composite powders proceeded several time faster than that with TiO_2 alone. Strong adsorption of MB on the powder was observed. This revealed spatial separation of photo-excited charges near the junction. (2) When Sr(Ti_<0.98>Nb_<0.02>)O_<3+δ> single crystal plate covered by TiO_2 thin film was used as a photo-electrode, the photo-current was larger 1.5 or 2 times than that for glass plate with FTO thin film covered by TiO_2 thin film. The TiO_2 thin film was prepared by sol-gel method. (When mono-light was irradiated, on-set wavelength for Sr(Ti_<0.98>Nb_<0.02>)O_<3+δ> single crystal / TiO_2 was shifted toward shorter wavelength 20 nm (0.1 eV) than that for FTO glass plate / TiO_2. (3)This proved the existence of spike in the heterojunction, end therefore this confirms the appearance of band-bending due to heterjunction. (4)The preparation of Sr(Ti_<i-x>Nb_5)O_<3+5>/ TiO_2 junction on the Ti-based alloy plates and controlling of ion adsorption on the composite powder were examined. (5) The controlling of the ion species adsorbed on the electrode must become important for photo-electrochemical reaction. The findings described above should be applied for highly efficient photo-electrochemical water splitting

半导体同质结和异质结引起的能带弯曲是光电极分解水高效制氢的关键因素。本研究制备了掺施主钛酸盐Sr（Ti_<1x>Nb_x）O_（3+5）的TiO_2复合粉体、单晶和薄膜，研究了复合粉体中的各种物理化学现象，即：研究了染料的光漂白、水分解光反应、染料敏化光电流和离子吸附。(1)Sr（Ti_<1-x>Nb_x）O_（3+δ）/ TiO_2复合粉体敏化亚甲基蓝水溶液的光漂白比单独使用TiO_2快几倍。观察到MB在粉末上的强吸附。这揭示了结附近光激发电荷的空间分离。(2)当Sr（Ti_<0.98>Nb_<0.02>）O_（3+δ）单晶片表面覆盖TiO_2薄膜时，其光电流比玻璃片表面覆盖FTO薄膜时的光电流大1.5 ~ 2倍。采用溶胶-凝胶法制备了TiO_2薄膜。(When在单光照射下，Sr（Ti_<0.98>Nb_<0.02>）O_（3+δ）单晶/TiO_2的起始波长比FTO玻璃板/TiO_2的起始波长向短波长方向移动了20 nm（0.1 eV）。（3）这证明了异质结中尖峰的存在，从而证实了异质结引起的能带弯曲的出现。（4）研究了<i-x>Ti基合金板上Sr（Ti_ Nb_5）O_（3+5）/TiO_2结的制备及复合粉末对离子吸附的控制。(5)控制吸附在电极上的离子种类对于光电化学反应必须变得重要。上述研究结果可应用于高效光电化学水分解