Thermodynamic Oxidation and Reduction Potentials of Photocatalytic Semiconductors in Aqueous Solution
Thermodynamic Oxidation and Reduction Potentials of Photocatalytic Semiconductors in Aqueous Solution
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DOI：
10.1021/cm302533s
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发表时间：
2012-09-25
影响因子：
8.6
通讯作者：
Wang, Lin-Wang
中科院分区：
文献类型：
--
作者：
Chen, Shiyou;Wang, Lin-Wang
介绍了一种计算水溶液中半导体热力学氧化还原电位的方法。通过结合新发展的从头计算方法的化合物的形成能量和能带排列的电化学实验数据，这种方法可以用来预测几乎任何化合物半导体在水溶液中的稳定性。三十光催化半导体已被研究，并产生一个图形（一个简化的Pourbaix图），显示它们的价/导带边缘和氧化/还原电位相对于水的氧化还原电位。在此基础上，分析了化合物半导体抗氧化和还原光腐蚀的热力学稳定性和趋势，结果表明：（1）某些金属氧化物作为n型光阳极时，可以抵抗光生空穴的氧化;（ii）所有的非氧化物半导体对氧化敏感，但是它们抵抗由光生电子引起的还原，因此如果被保护免于氧化，则可以用作p型光电阴极;（iii）用较少的电负性阴离子掺杂或合金化金属氧化物可减小带隙，但也降低抗氧化的稳定性。
An approach is introduced to calculate the thermodynamic oxidation and reduction potentials of semiconductors in aqueous solution. By combining a newly developed ab initio calculation method for compound formation energy and band alignment with electrochemistry experimental data, this approach can be used to predict the stability of almost any compound semiconductor in aqueous solution. Thirty photocatalytic semiconductors have been studied, and a graph (a simplified Pourbaix diagram) showing their valence/conduction band edges and oxidation/reduction potentials relative to the water redox potentials is produced. On the basis of this graph, the thermodynamic stabilities and trends against the oxidative and reductive photocorrosion for compound semiconductors are analyzed, which shows the following: (i) some metal oxides can be resistant against the oxidation by the photogenerated holes when used as the n-type photoanodes; (ii) all the nonoxide semiconductors are susceptible to oxidation, but they are resistant to the reduction by the photogenerated electrons and thus can be used as the p-type photocathodes if protected from the oxidation; (iii) doping or alloying the metal oxide with less electronegative anions can decrease the band gap but also degrade the stability against oxidation.