Controlling electronic properties of MoS2/graphene oxide heterojunctions for enhancing photocatalytic performance: the role of oxygen

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 an...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2018, Vol.20 (3), p.1974-1983
Main Authors: Hua, Xiaotian, Ma, Xinguo, Hu, Jisong, He, Hua, Xu, Guowang, Huang, Chuyun, Chen, Xiaobo
Format: Article
Language:English
Subjects:
Catalytic activity
Conduction bands
Doppler effect
Electric fields
Electromagnetic absorption
Electronic properties
First principles
Graphene
Heterojunctions
Interlayers
Molybdenum disulfide
Photocatalysis
Red shift
Valence band
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Summary: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.
ISSN:1463-9076
1463-9084
DOI:10.1039/c7cp07303h