Au nanoparticles@MoS₂core-shell structures with moderate MoS₂coverage for efficient photocatalytic water splitting

Metal nanoparticles (NPs)@MoS₂core-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 MoS₂on the photocatalytic water splitting. Here, we systematically study the effect of the MoS₂coverage on the photocatalytic water splitting in the Au NPs@MoS₂core-shell hybrid structures. The different MoS₂coverage on the Au NPs can be obtained through tuning the hydrothermal reaction time from 3 h to 18 h. We find that the moderate MoS₂coverage (i.e. 12 h) can ensure the H₂O molecules penetrating the MoS₂shell and reaching to the Au-MoS₂junctions. In addition, the moderate MoS₂coverage is beneficial for the incident light to excite the strong plasmonic effect around the Au NPs core. The most efficient separation efficiency of electron–hole pairs in the Au NPs@MoS₂core-shell structure with the moderate MoS₂coverage is also possible reason for the high performance photocatalytic water splitting. As a result, the moderate MoS₂coverage shows the largest yield of hydrogen gas production (2110.7 μmol) among the Au NPs@MoS₂core-shell structures. In addition, the yield of hydrogen gas production is also obvious higher than that of the pure MoS₂spheres (880.0 μmol/g) and simple mixture of Au NPs and MoS₂sphere (1380.3 μmol/g). Our study strengthens the significance of the moderate MoS₂coverage in the Au NPs@MoS₂core-shell structures for high-performance photocatalytic water splitting.