Highly Facet-Dependent Photocatalytic Properties of Cu2 O Crystals Established through the Formation of Au-Decorated Cu2 O Heterostructures.
Highly Facet-Dependent Photocatalytic Properties of Cu2 O Crystals Established through the Formation of Au-Decorated Cu2 O Heterostructures.
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DOI：
10.1002/chem.201602173
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发表时间：
2016-08
期刊：
影响因子：
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通讯作者：
G. Yuan;Chi-Fu Hsia;Zhen-Wen Lin;Chieh-Chun Chiang;Y. Chiang;Michael H. Huang
中科院分区：
文献类型：
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作者：
G. Yuan;Chi-Fu Hsia;Zhen-Wen Lin;Chieh-Chun Chiang;Y. Chiang;Michael H. Huang
这项工作证实了存在一个大的面依赖于Cu 2 O晶体的光催化活性，通过稀疏沉积的金颗粒上的Cu 2 O立方体，八面体，和菱形十二面体。Au修饰的Cu 2 O菱形十二面体和八面体表现出极大的增强的光降解率的甲基橙产生的光生电子和空穴的更好的分离，与菱形十二面体给最好的效率。Au-Cu 2 O核壳菱形十二面体的光催化活性也优于原始菱形十二面体。然而，Au沉积的Cu 2 O立方体，原始立方体，和Au沉积的小纳米立方体完全{100}面约束的光催化活性。X射线光电子能谱（XPS）显示相同的铜峰的位置，这些金装饰的晶体。值得注意的是，电子顺磁共振（EPR）测量表明，较高的生产羟基自由基的光照射的Cu 2 O菱形十二面体比八面体，但没有自由基产生从光照射的Cu 2 O立方体。Cu 2 O {100}面可以通过其大的能带边缘弯曲和/或静电排斥而呈现高能量势垒，从而防止电荷载流子到达该表面。在这种情况下，传统的网络模型失败了。在其他半导体系统中，当光致电荷转移过程发生在界面上时，应可观察到小面依赖的光催化差异。
This work confirms the presence of a large facet-dependent photocatalytic activity of Cu2 O crystals through sparse deposition of gold particles on Cu2 O cubes, octahedra, and rhombic dodecahedra. Au-decorated Cu2 O rhombic dodecahedra and octahedra showed greatly enhanced photodegradation rates of methyl orange resulting from a better separation of the photogenerated electrons and holes, with the rhombic dodecahedra giving the best efficiency. Au-Cu2 O core-shell rhombic dodecahedra also displayed a better photocatalytic activity than pristine rhombic dodecahedra. However, Au-deposited Cu2 O cubes, pristine cubes, and Au-deposited small nanocubes bound by entirely {100} facets are all photocatalytically inactive. X-ray photoelectron spectra (XPS) showed identical copper peak positions for these Au-decorated crystals. Remarkably, electron paramagnetic resonance (EPR) measurements indicated a higher production of hydroxyl radicals for the photoirradiated Cu2 O rhombic dodecahedra than for the octahedra, but no radicals were produced from photoirradiated Cu2 O cubes. The Cu2 O {100} face may present a high energy barrier through its large band edge bending and/or electrostatic repulsion, preventing charge carriers from reaching to this surface. The conventional photocatalysis model fails in this case. The facet-dependent photocatalytic differences should be observable in other semiconductor systems whenever a photoinduced charge-transfer process occurs across an interface.