Charge separation between polar {111} surfaces of CoO octahedrons and their enhanced visible-light photocatalytic activity.
Charge separation between polar {111} surfaces of CoO octahedrons and their enhanced visible-light photocatalytic activity.
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DOI：
10.1021/am508357x
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发表时间：
2015-03
影响因子：
9.5
通讯作者：
B. Liu;Lan Ma;Lichao Ning;Congjie Zhang;Guoping Han;C. Pei;Hua Zhao;Shengzhong Liu;Heqing Yang-Heq
中科院分区：
文献类型：
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作者：
B. Liu;Lan Ma;Lichao Ning;Congjie Zhang;Guoping Han;C. Pei;Hua Zhao;Shengzhong Liu;Heqing Yang-Heq
半导体的晶面工程已被证明是提高光催化性能的有效策略。然而，涉及到的机制尚不清楚。在此，我们报告了我们的成功，在Cl（-）离子覆盖的CoO八面体与暴露的{111}面的光催化性能被激活的AgNO 3和NH3·H2O溶液的处理。清洁的CoO {111}面被发现是高反应性的面。基于暴露{111}面的极性结构，提出了极性{111}面之间的电荷分离模型。由于自发极化，在极性{111}面之间存在内部电场。内部电场为电荷分离提供驱动力。还原和氧化反应选择性地发生在正极性和负极性{111}表面上。电荷分离模型为高光催化活性半导体纳米晶体中的电荷转移提供了清晰的认识，为设计更有效的光催化剂、太阳能电池、光电极等光电器件提供了指导。
Crystal facet engineering of semiconductors has been proven to be an effective strategy to increase photocatalytic performances. However, the mechanism involved in the photocatalysis is not yet known. Herein, we report our success in that photocatalytic performances of the Cl(-) ion capped CoO octahedrons with exposed {111} facets were activated by a treatment using AgNO3 and NH3·H2O solutions. The clean CoO {111} facets were found to be highly reactivity faces. On the basis of the polar structure of the exposed {111} surfaces, a charge separation model between polar {111} surfaces is proposed. There is an internal electric field between polar {111} surfaces due to the spontaneous polarization. The internal electric field provides a driving force for charge separation. The reduction and oxidation reactions selectively take place on the positive and negative polar {111} surfaces. The charge separation model provides a clear insight into charge transfer in the semiconductor nanocrystals with high photocatalytic activities and offer guidance to design more effective photocatalysts, solar cells, photoelectrodes, and other photoelectronic devices.