Herein a rich, Se-nanoparticle modified Mo-W18O49 nanocomposite as efficient hydrogen evolution reaction catalyst is reported via hydrothermal synthesized process. In this work, Na2SeSO3 solution and selenium powder are used as Se precursor material. The structure and composition of the nanocomposites are characterized by X-ray diffraction (XRD), high-resolution field emission scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), EDX spectrum analysis and the corresponding element mapping. The improved electrochemical properties are studied by current density, and EIS analysis. The as-prepared Se modified Mo-W18O49 synthesized via Na2SeSO3 is investigated by FE-SEM analysis and found to exhibit spherical particles combined with nanosheets. This special morphology effectively improves the charge separation and transfer efficiency, resulting in enhanced photoelectric behavior compared with that of pure Mo-W18O49. The nanomaterial obtained via Na2SeSO3 solution demonstrates a high HER activity and low overpotential of -0.34 V, allowing it to deliver a current density of 10 mA cm2.

Abstract
1. Introduction
2. Experimental Details
    2.1. Materials
    2.2. Preparation of electrocatalysts
    2.3. Characterization
    2.4. Preparation of catalytic electrodes
3. Results and Discussion
    3.1. Phase and morphology
    3.2. Chemical state
    3.3. Electrochemical performance
    References
4. Conclusion

• Jun Hui Wang
• Jia-Yao Tang
• Jia-Yi Fan
• Ze-Da Meng
• Lei Zhu Corresponding author
• Won-Chun Oh Corresponding author