Tuning interlayer spacing of MoS₂ for enhanced hydrogen evolution reaction

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.