Facet-Dependent Photoreduction on Single ZnO Crystals
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- 作者：Elke Debroye ; Jordi Van Loon ; Haifeng YuanKris P. F. Janssen ; Zaizhu Lou ; Sooyeon Kim ; Tetsuro Majima ; Maarten B. J. Roeffaers
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2017
- 出版时间：January 19, 2017
- 年：2017
- 卷：8
- 期：2
- 页码：340-346
- 全文大小：480K
- ISSN：1948-7185
文摘
Photocatalytic reactions occur at the crystal–solution interface, and hence specific crystal facet expression and surface defects can play an important role. Here we investigate the structure-related photoreduction at zinc oxide (ZnO) microparticles via integrated light and electron microscopy in combination with silver metal photodeposition. This enables a direct visualization of the photoreduction activity at specific crystallographic features. It is found that silver nanoparticle photodeposition on dumbbell-shaped crystals mainly takes place at the edges of O-terminated (0001̅) polar facets. In contrast, on ZnO microrods photodeposition is more homogeneously distributed with an increased activity at {101̅1̅} facets. Additional time-resolved measurements reveal a direct spatial link between the enhanced photoactivity and increased charge carrier lifetimes. These findings contradict previous observations based on indirect, bulk-scale experiments, assigning the highest photocatalytic activity to polar facets. The presented research demonstrates the need for advanced microscopy techniques to directly probe the location of photocatalytic activity.