Direct Observation of Charge Separation on Anatase TiO2 Crystals with Selectively Etched {001} Facets

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• 作者：Xiaogang Liu ; Guojun Dong ; Shaopeng Li ; Gongxuan Lu ; Yingpu Bi
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：March 9, 2016
• 年：2016
• 卷：138
• 期：9
• 页码：2917-2920
• 全文大小：344K
• ISSN：1520-5126

文摘

Synchronous illumination X-ray photoelectron spectroscopy (SIXPS) was employed for the first time to directly identify the photogenerated charge separation and transfer on anatase TiO₂ single-crystals with selectively etched {001} facets. More specifically, for the TiO₂ crystals with intact {001} and {101} facets, most of photogenerated charge carriers rapidly recombined, and no evident electron–hole separation was detected. With selectively etching on {001} facets, high efficient charge separation via hole transfer to titanium and electron to oxygen was clearly observed. However, when the {001} facets were completely etched into a hollow structure, the recombination for photogenerated electron–hole pairs would dominate again. These demonstrations clearly reveal that the appropriate corrosion on {001} facets could facilitate more efficient electron–hole separation and transfer. As expected, the optimized TiO₂ microcrystals with etched {001} facets could achieve a hydrogen generation rate of 74.3 μmol/h/g, which is nearly 7 times higher than the intact-TiO₂ crystals.