Huang Xiaoqian, Gao Xiaoru, Xue Qihui, Wang Can, Zhang Ruikang, Gao Yuanzhe, Han Zhangang
National Demonstration Center for Experimental Chemistry Education, Hebei Key Laboratory of Organic Functional Molecules, College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang, Hebei 050024, China.
Dalton Trans. 2020 Feb 21;49(7):2184-2189. doi: 10.1039/c9dt04374h. Epub 2020 Jan 30.
Oxygen vacancies are recognized as the most prevalent defects in oxide materials. The effect of oxygen vacancies on the physicochemical properties of metal oxide semiconductors has attracted considerable attention in the photocatalysis field. But so far, the impact of oxygen vacancies on charge carrier transfer for photoelectrochemical water splitting has been unclear. In this work, TiO photoanodes with various oxygen vacancy concentrations were studied as metal oxide models to clarify the impact of oxygen vacancies on charge carrier transfer behaviors. The potential distribution and electrochemical impedance spectroscopy results indicate that the oxygen vacancies facilitate charge carrier diffusion in TiO, but are disadvantageous for the charge carrier drift in the TiO/electrolyte interface. The TiO-400 photoanode with intermediate oxygen vacancy concentration exhibits the highest photocurrent density. It is expected that this work will provide reference to design and fabricate oxide semiconductors as photoanodes for higher charge carrier utilization in the field of solar-to-chemical energy conversion.
氧空位被认为是氧化物材料中最普遍的缺陷。氧空位对金属氧化物半导体物理化学性质的影响在光催化领域引起了相当大的关注。但到目前为止，氧空位对光电化学水分解中电荷载流子转移的影响尚不清楚。在这项工作中，研究了具有不同氧空位浓度的TiO光阳极作为金属氧化物模型，以阐明氧空位对电荷载流子转移行为的影响。电位分布和电化学阻抗谱结果表明，氧空位促进了TiO中电荷载流子的扩散，但不利于TiO/电解质界面中电荷载流子的漂移。具有中等氧空位浓度的TiO-400光阳极表现出最高的光电流密度。预计这项工作将为设计和制造氧化物半导体作为光阳极提供参考，以便在太阳能到化学能转换领域中实现更高的电荷载流子利用率。
