BiVO4 {010} and {110} Relative Exposure Extent: Governing Factor of Surface Charge Population and Photocatalytic Activity

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• 作者：Hui Ling Tan ; Xiaoming Wen ; Rose Amal ; Yun Hau Ng
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2016
• 出版时间：April 7, 2016
• 年：2016
• 卷：7
• 期：7
• 页码：1400-1405
• 全文大小：415K
• ISSN：1948-7185

文摘

The {010} and {110} crystal facets of monoclinic bismuth vanadate (m-BiVO₄) has been demonstrated to be the active reduction and oxidation sites, respectively. Here, we show using dual-faceted m-BiVO₄ with distinctly different dominant exposed facets, one which is {010}-dominant and the other {110}-dominant, contrary to prediction, the former m-BiVO₄ exhibits superior photooxidation activities. The population of photogenerated electrons and holes on the surface are revealed to be proportional to the respective surface areas of {010} and {110} exposed on m-BiVO₄, as evidenced by steady-state photoluminescence (PL) measurements in the presence of charge scavengers. The better photoactivity of {010}-dominant m-BiVO₄ is attributed to prompt electron transfer facilitated by the presence of more photogenerated electrons on the larger {010} surface. Additionally, the greater extent of electron trapping in {110}-dominant m-BiVO₄ also deteriorates its photoactivity by inducing electron–hole pair recombination.