Significance of Hydroxyl Radical in Photoinduced Oxygen Evolution in Water on Monoclinic Bismuth Vanadate
Significance of Hydroxyl Radical in Photoinduced Oxygen Evolution in Water on Monoclinic Bismuth Vanadate
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DOI：
10.1021/acs.jpcc.7b03641
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发表时间：
2017-11
影响因子：
3.7
通讯作者：
Yukihiro Nakabayashi;M. Nishikawa;N. Saito;C. Terashima;A. Fujishima
中科院分区：
文献类型：
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作者：
Yukihiro Nakabayashi;M. Nishikawa;N. Saito;C. Terashima;A. Fujishima
了解单斜晶系钒酸铋（m-BiVO 4）光氧化水的机理对于太阳光下有效的氧气（O2）释放是非常有趣的。羟基（OH）自由基被证实在m-BiVO 4粉末的光催化体系。OH自由基具有高度反应性，可二聚成过氧化氢（H2 O2），后者进一步氧化成O2分子。因此，从OH自由基O2的演变可能是一个合理的机制。在本研究中，阐明了O2从OH自由基的意义，O2分子和OH自由基的光电化学水氧化m-BiVO 4电极上产生。O2分子和OH自由基的量分别通过使用测氧仪和荧光探针法进行定量。OH自由基形成的光电流的电流效率（约0.06%）远小于O2释放的光电流的电流效率（约100%），表明在m-BiVO 4上OH自由基的O2释放并不显著。
Understanding the details of the mechanism of water photo-oxidation on monoclinic bismuth vanadate (m-BiVO4) is intriguing for efficient oxygen (O2) evolution under solar light. Hydroxyl (OH) radical was confirmed in a photocatalytic system of m-BiVO4 powders. OH radical is highly reactive to dimerize into hydrogen peroxide (H2O2), which is further oxidized into O2 molecule. Therefore, O2 evolution from OH radicals could be one of the plausible mechanisms. In the present study, to clarify the significance of O2 evolution from OH radicals, O2 molecules and OH radicals were generated by photoelectrochemical water oxidation on m-BiVO4 electrode. The amounts of O2 molecules and OH radicals were quantified by using an oxygen meter and a fluorescence probe method, respectively. The current efficiency of the photocurrent for the formation of OH radicals (∼0.06%) was much smaller than that for O2 evolution (∼100%), indicating that O2 evolution from OH radicals was not significant on m-BiVO4.