Spatial separation of photogenerated electrons and holes among {010} and {110} crystal facets of BiVO4
Spatial separation of photogenerated electrons and holes among {010} and {110} crystal facets of BiVO4
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DOI：
10.1038/ncomms2401
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发表时间：
2013-02-01
影响因子：
16.6
通讯作者：
Li, Can
中科院分区：
文献类型：
--
作者：
Li, Rengui;Zhang, Fuxiang;Li, Can
电荷分离是提高半导体光催化剂活性的关键，特别是在水分解反应中。本文以单斜钒酸铋晶体为模型光催化剂，在光照射下，在{010}和{110}晶面上分别发生了光生电子还原反应和光生空穴氧化反应，证明了在不同晶面上可以实现有效的电荷分离。基于这一发现，还原和氧化共催化剂分别选择性地沉积在{010}和{110}上，与随机分布的共催化剂相比，光催化和光电催化水氧化反应的活性都要高得多。这些结果表明，光生电子和空穴可以在半导体晶体的不同面之间分离。这一发现对于构建高效的太阳能转换系统具有重要的半导体物理和化学意义。
Charge separation is crucial for increasing the activity of semiconductor-based photocatalysts, especially in water splitting reactions. Here we show, using monoclinic bismuth vanadate crystal as a model photocatalyst, that efficient charge separation can be achieved on different crystal facets, as evidenced by the reduction reaction with photogenerated electrons and oxidation reaction with photogenerated holes, which take place separately on the {010} and {110} facets under photo-irradiation. Based on this finding, the reduction and oxidation cocatalysts are selectively deposited on the {010} and {110} facets respectively, resulting in much higher activity in both photocatalytic and photoelectrocatalytic water oxidation reactions, compared with the photocatalyst with randomly distributed cocatalysts. These results show that the photogenrated electrons and holes can be separated between the different facets of semiconductor crystals. This finding may be useful in semiconductor physics and chemistry to construct highly efficient solar energy conversion systems.