In3+-doped BiVO4 photoanodes with passivated surface states for photoelectrochemical water oxidation
In3+-doped BiVO4 photoanodes with passivated surface states for photoelectrochemical water oxidation
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具有钝化表面态的 In3 掺杂 BiVO4 光阳极用于光电化学水氧化
DOI：
10.1039/c8ta01377b
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发表时间：
2018-06-14
影响因子：
11.9
通讯作者：
Zhou, Yong
中科院分区：
文献类型：
--
作者：
Zhong, Xiaohui;He, Huichao;Zhou, Yong
BiVO 4是一种很有前途的光电化学分解水的光阳极材料，但其高能表面态阻碍了其实际活性。在这里，我们报告说，In 3+可以作为掺杂剂，以取代Bi 3+在BiVO 4中的部分位置，用于修改表面状态和改善BiVO 4纳米片膜的水氧化活性。In 3+掺杂BiVO 4薄膜光阳极中，In 3+掺杂量为7%的BiVO 4薄膜具有最佳的光电化学水氧化活性。在1.23 V vs. RHE下，7% In 3+掺杂的BiVO 4光阳极在0.1 M Na 2SO 4中表现出1.56 mA cm（-2）的光电流密度，这比未掺杂的BiVO 4光阳极的光电流密度大200%以上。In ~（3+）掺杂对BiVO_4的形貌、物相和禁带宽度没有明显影响，但使BiVO_4的平带位置正移，提高了水氧化的表面电荷分离效率。密度泛函理论计算表明，In 3+掺杂后BiVO 4的表面能降低，使Bi原子的不饱和电子更多地参与Bi-O键，从而减少了暴露的不饱和Bi原子和断裂的Bi-O键。因此，In 3+掺杂BiVO 4光阳极上增强的水氧化活性可以归因于In 3+掺杂钝化BiVO 4的表面状态，从而抑制表面电荷复合。
BiVO4 is a promising photoanode material for photoelectrochemical water splitting, but its actual activity is hindered by the high energy surface states. Here, we report that In3+ can be used as a dopant to substitute the partial sites of Bi3+ in BiVO4 for modifying the surface states and improving the water oxidation activity of a BiVO4 nanoflake film. Among the In3+-doped BiVO4 film photoanodes, the 7% In3+-doped BiVO4 film shows optimal photoelectrochemical water oxidation activity. At 1.23 V vs. RHE, the 7% In3+-doped BiVO4 photoanode exhibits a photocurrent density of 1.56 mA cm(-2) in 0.1 M Na2SO4, which is over 200% greater than that of the undoped BiVO4 photoanode. In3+-doping did not change the morphology, phase and band gap of BiVO4 obviously, but resulted in a positive shift of the flat band position and higher surface charge separation efficiency for water oxidation. Density functional theory calculations indicate that the surface energy of BiVO4 decreased after In3+-doping that involved more unsaturated electrons of the Bi atom in the Bi-O bonds, thus reducing the amount of exposed unsaturated Bi atoms and broken Bi-O bonds. Therefore, the enhanced water oxidation activity on the In3+-doped BiVO4 photoanode can be ascribed to In3+-doping that passivated the surface states of BiVO4 and thus inhibited the surface charge recombination.