Time-Resolved Infrared Absorption Study of SrTiO3 Photocatalysts Codoped with Rhodium and Antimony
Time-Resolved Infrared Absorption Study of SrTiO3 Photocatalysts Codoped with Rhodium and Antimony
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DOI：
10.1021/jp407040p
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发表时间：
2013-09-19
影响因子：
3.7
通讯作者：
Onishi, Hiroshi
中科院分区：
文献类型：
--
作者：
Furuhashi, Koji;Jia, Qingxin;Onishi, Hiroshi
采用水热法制备了Rh和Sb掺杂的SrTiO 3光催化剂。单独掺杂Rh会导致以580和420 nm为中心的光吸收，这归因于Rh 4+和Rh 3+。加入Sb后，Rh的氧化态变为3+，580 nm处的吸收消失。当用355或532 nm光脉冲泵浦时，掺杂和未掺杂的光催化剂在3000-1000 cm（-1）处由于激发电子而表现出瞬态红外吸收。在真空中观察到吸收衰减作为微秒时间延迟的函数，以推断电子-空穴复合的相对速率。Rh 4+作为复合中心的活性作用通过单独掺杂Rh的光催化剂具有最快的吸光度衰减来证明。在Sb的存在下，衰减延迟，以显示Rh 3+在复合中的有限作用。在甲醇水溶液中的稳态H-2生产检查在掺杂SrTiO 3光催化剂上的Pt助催化剂的存在下。通过比较的H-2的生产率与复合率，一个共同的效率，电子到H-2的转换建议，无论不同的掺杂剂组合物。在AgNO 3溶液中观察到的O-2的生产率的基础上，空穴到O-2的转换效率建议是敏感的掺杂剂组合物。
In this study, SrTiO3 photocatalysts doped with Rh and Sb are prepared by hydrothermal synthesis. Doping Rh alone causes optical absorption centered at 580 and 420 nm, attributed to Rh4+ and Rh3+. By adding Sb, the oxidation state of Rh shifts to be 3+ and the absorption at 580 nm disappears. The doped and nondoped photocatalysts exhibit transient infrared absorption at 3000-1000 cm(-1) due to excited electrons, when pumped by 355 or 532 nm light pulses. The absorbance decay is observed in a vacuum as a function of microsecond time delays to deduce the relative rate of electron-hole recombination. The active role of Rh4+ as a recombination center is evidenced by the photocatalyst doped with Rh alone having the fastest absorbance decay. The decay retards in the presence of Sb to show the limited role of Rh3+ in recombination. Steady-state H-2 production in an aqueous methanol solution is examined in the presence of Pt cocatalyst on the doped SrTiO3 photocatalysts. By comparing the H-2 production rate with the recombination rate, a common efficiency of electron-to-H-2 conversion is suggested, regardless of different dopant compositions. On the basis of the O-2 production rate observed in a AgNO3 solution, the hole-to-O-2 conversion efficiency is suggested to be sensitive to the dopant compositions.