Tan Hui Ling, Wen Xiaoming, Amal Rose, Ng Yun Hau
Particles and Catalysis Research Group, School of Chemical Engineering, and ‡Australian Centre for Advanced Photovoltaics, School of Photovoltaic and Renewable Energy Engineering, The University of New South Wales , Sydney, New South Wales 2052, Australia.
J Phys Chem Lett. 2016 Apr 7;7(7):1400-5. doi: 10.1021/acs.jpclett.6b00428. Epub 2016 Mar 29.
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.
单斜钒酸铋（m-BiVO4）的{010}和{110}晶面已分别被证明是活性还原和氧化位点。在此，我们展示了使用具有明显不同主要暴露面的双晶面m-BiVO4，一种以{010}为主，另一种以{110}为主，与预测相反，前者m-BiVO4表现出优异的光氧化活性。通过在存在电荷清除剂的情况下进行稳态光致发光（PL）测量证明，m-BiVO4表面光生电子和空穴的数量与{010}和{110}各自暴露的表面积成正比。{010}为主的m-BiVO4具有更好的光活性，这归因于在较大的{010}表面上存在更多光生电子促进了电子的快速转移。此外，{110}为主的m-BiVO4中更大程度的电子俘获也通过诱导电子-空穴对复合而降低了其光活性。
