Effects of oxygen doping on optical band gap and band edge positions of Ta3N5 photocatalyst: A GGA + U calculation
Effects of oxygen doping on optical band gap and band edge positions of Ta3N5 photocatalyst: A GGA + U calculation
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DOI：
10.1016/j.jcat.2013.10.014
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发表时间：
2014
影响因子：
7.3
通讯作者：
Jiajia Wang;Tao Fang;Li Zhang;Jianyong Feng;Zhaosheng Li;Z. Zou
中科院分区：
文献类型：
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作者：
Jiajia Wang;Tao Fang;Li Zhang;Jianyong Feng;Zhaosheng Li;Z. Zou
采用GGA + U方法研究了氧掺杂对Ta 3 N5光学带隙和带边位置的影响。结果表明，掺氧Ta 3 N5的光学带隙与氧浓度有关。随着氧浓度的增加，掺氧Ta 3 N5薄膜的光学带隙先减小后增大，与实验结果一致.掺氧Ta 3 N5的光学带隙与氧浓度的关系可以用Burstein-Moss效应和带隙窄化效应的竞争来解释，它们分别使半导体的光学带隙增大和减小.与纯Ta 3 N5相比，氧掺杂提高了Ta 3 N5的水氧化能力，但降低了Ta 3 N5的水还原能力，表明杂质氧是限制Ta 3 N5光催化性能的一个重要来源。
Density functional theory calculations with the GGA + U method have been carried out to study the effects of oxygen doping on the optical band gaps and band edge positions of the O-doped Ta3N5. The results showed that the optical band gaps of O-doped Ta3N5were oxygen concentration dependent. With the increase in oxygen concentration, the optical band gap of O-doped Ta3N5first decreased and then increased, agreeing well with the experimental observations. The relation between optical band gap and oxygen concentration in O-doped Ta3N5can be explained by the competition between Burstein–Moss and band gap narrowing effects, which enlarged and reduced the optical band gap of a semiconductor, respectively. Compared with the pure Ta3N5, doping with oxygen improved the water oxidation ability but lowered the water reduction ability of Ta3N5, suggesting that the impurity oxygen is one proper source that limit the photocatalytic performance of Ta3N5.