Au nanoparticles@MoS2 core-shell structures with moderate MoS2 coverage for efficient photocatalytic water splitting

Metal nanoparticles (NPs)@MoS2 core-shell nanostructures as plasmon-enhanced photocatalysts have been studied recently for efficiently photocatalytic water splitting. However, there is few reports about the effect of coverage of MoS2 on the photocatalytic water splitting. Here, we systematically study the effect of the MoS2 coverage on the photocatalytic water splitting in the Au NPs@MoS2 core-shell hybrid structures. The different MoS2 coverage on the Au NPs can be obtained through tuning the hydrothermal reaction time from 3 h to 18 h. We find that the moderate MoS2 coverage (i.e. 12 h) can ensure the H2O molecules penetrating the MoS2 shell and reaching to the Au-MoS2 junctions. In addition, the moderate MoS2 coverage is beneficial for the incident light to excite the strong plasmonic effect around the Au NPs core. The most efficient separation efficiency of electronehole pairs in the Au NPs@MoS2 core-shell structure with the moderate MoS2 coverage is also possible reason for the high performance photo-catalytic water splitting. As a result, the moderate MoS2 coverage shows the largest yield of hydrogen gas production (2110.7 mu mol) among the Au NPs@MoS2 core-shell structures. In addition, the yield of hydrogen gas production is also obvious higher than that of the pure MoS2 spheres (880.0 mu mol/g) and simple mixture of Au NPs and MoS2 sphere (1380.3 mu mol/g). Our study strengthens the significance of the moderate MoS2 coverage in the Au NPs@MoS2 core-shell structures for high-performance photocatalytic water splitting. (C) 2017 Elsevier B.V. All rights reserved.