Amorphous molybdenum sulfide ( MoSx) has been regarded as a promising hydrogen evolution reaction (HER) catalyst due to its mild preparation conditions and low-cost precursor materials. In this work, we report a simple strategy combining the growth of amorphous MoSx on the surface of metal organic frameworks (ZIF-67) and annealing treatment to prepare Co-doped MoSx nanopolyhedrons (denoted as CoMoSx NPs). The CoMoSx NPs exhibit excellent HER activity in acid condition with an overpotential of 188 mV at a current density of 10 mA cm− 2 (η10), and a relatively stable overpotential after 2000 cyclic voltammetry (CV) cycles testing. The excellent HER performance of the CoMoSx NPs can be attributed to the doping of Co element adjust the electronic structure and increase the conductivity of catalyst, and the nanopolyhedrons structure which can expose more active sites for HER electrocatalytic. This study offers a low-cost and simple strategy to prepare high-activity HER catalyst, which holds great promises in developing advanced electrocatalysts for energy storage.

Co-doped amorphous MoSx for efficient hydrogen evolution reaction in acid condition
    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 Synthesis of ZIF-67
        2.3 Synthesis of CoMoSx NPs
        2.4 Synthesis of CoMoSx
        2.5 Synthesis of MoSx
        2.6 Characterization
        2.7 Preparation of working electrode
        2.8 Electrochemical measurements
    3 Results and discussion
        3.1 Micromorphology characterization of CoMoSx NPs
        3.2 Composition characterization of CoMoSx NPs
        3.3 BET surface area characterization of CoMoSx NPs
        3.4 Elemental composition and valence characterization of CoMoSx NPs
        3.5 Electrochemical characterization of CoMoSx NPs
    4 Conclusions
    Acknowledgements 
    References

• Lang Gan(Key Laboratory of Efficient & Clean Energy Utilization, School of Energy and Power Engineering, Changsha University of Science & Technology, Changsha 410114, China)
• Jincheng Liu(Key Laboratory of Efficient & Clean Energy Utilization, School of Energy and Power Engineering, Changsha University of Science & Technology, Changsha 410114, China)
• Yanjie Ren(Key Laboratory of Efficient & Clean Energy Utilization, School of Energy and Power Engineering, Changsha University of Science & Technology, Changsha 410114, China)
• Zhongyi Xiong(Key Laboratory of Efficient & Clean Energy Utilization, School of Energy and Power Engineering, Changsha University of Science & Technology, Changsha 410114, China)
• Kang Chen(Recycling Economy Science and Technology Innovation Center of National Energy Group Shenhua Harwusu Open Pit, Erdos 010300, Inner Mongolia, China)