Controlling electronic properties of MoS2/graphene oxide heterojunctions for enhancing photocatalytic performance: the role of oxygen.
Controlling electronic properties of MoS2/graphene oxide heterojunctions for enhancing photocatalytic performance: the role of oxygen.
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DOI：
10.1039/c7cp07303h
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发表时间：
2018-01
期刊：
影响因子：
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通讯作者：
Xiaotian Hua;Xinguo Ma;Jisong Hu;Hua He;Guowang Xu;Chuyun Huang;Xiaobo Chen
中科院分区：
文献类型：
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作者：
Xiaotian Hua;Xinguo Ma;Jisong Hu;Hua He;Guowang Xu;Chuyun Huang;Xiaobo Chen
调控新型异质光催化剂的组分是提高光催化效率的有效方法，但对层间相互作用与光催化活性之间的关系还缺乏理论认识。本文采用第一性原理计算方法系统地研究了不同氧浓度下MoS 2/氧化石墨烯（GO）异质结的界面相互作用和电子性质。结果表明，MoS 2与GO形成稳定的货车德瓦尔斯异质结，界面平衡后，随着O浓度的增加，GO到MoS 2表面的内建电场增强。据推测，光生电子和空穴自然积累在GO的导带和价带的MoS 2，分别在内置的内部电场驱动下，表明直接Z-方案异质结的形成。另外，随着氧浓度的增加，MoS 2/GO异质结的光吸收边发生红移，导带边发生上移.结果表明，O原子在MoS 2/GO异质结的能带排列中起着至关重要的作用。这些结果对理解和设计层状MoS 2/GO光催化体系或与其他半导体作为助催化剂具有重要意义。
The manipulation of the constituents of novel hetero-photocatalysts is an effective method for improving photocatalytic efficiency, but a theoretical understanding of the relationship between interlayer interaction and photocatalytic activity is still lacking. Herein, the interfacial interactions and electronic properties of MoS2/graphene oxide (GO) heterojunctions with various O concentrations were explored systematically by first-principles calculations. The results indicate that MoS2 and GO can form a stable van der Waals heterojunction, and enhance the built-in internal electric field from GO to the MoS2 surface with the increase in O concentration after interfacial equilibrium. It is inferred that the photogenerated electrons and holes naturally accumulate in the conduction band of GO and the valence band of MoS2, respectively, under the built-in internal electric field driving, indicating the formation of direct Z-scheme heterojunctions. In addition, a red shift of the light absorption edge and the shift up of the conduction band edge of MoS2/GO heterojunctions are observed with an increase in O concentration. It can be concluded that the O atom plays a crucial role in the energy band alignment of MoS2/GO heterojunctions for the improvement of photocatalytic performance. These results are beneficial to understand and design layered MoS2/GO photocatalytic systems or as cocatalysts with other semiconductors.