Tuning Interlayer Spacing of MoS2 for Enhanced Hydrogen Evolution Reaction

Abstract The MoS2 structure engineering including hybrid structure construction and material self-optimization (edge sites improvement and phase transition), is a potential solution to boost photocatalytic hydrogen evolution reaction (HER) performance. Among the influence factors to MoS2 structure, the interlayer distance, which is a significant and non-ignorable parameter, plays a momentous role in tuning the photoelectric property and photocatalytic activity of MoS2. Here, we prepare MoS2 with different interlayer distances, and explore the corresponding optical and electrical properties. As the MoS2 interlayer spacing expands, the MoS2-1.12 (interlayer spacing 1.12 nm) is equipped with optimal light absorption ability, broadened energy band structure, high carrier mobility, and good electron transfer performance, compared to the MoS2-0.87 (interlayer spacing 0.87 nm) and MoS2-0.62 (interlayer spacing 0.62 nm). Consequently, the sample MoS2-1.12 possesses better HER performance (hydrogen production rate 311.28 μmol/g/h) than the MoS2-0.87 and MoS2-0.62. In addition, the MoS2 @Au core-shell structure with optimal interlayer distance is designed to further enhance the HER ability, and the H2 production rate of the MoS2-1.12@Au (773.4 μmol/g/h) is 2.48 times than that of the MoS2-1.12. The remarkable enhancement originates from the additional plasmonic Au nanoparticles. These results are significant for developing promising MoS2-based photocatalysts in the field of photocatalytic HER.