Research On Preparation And Performance Of Mo Group Compounds In Hydrogen Evolution Reaction

Electrolysis of water to produce hydrogen is one of the most potential ways to produce hydrogen.At present,non-noble metal catalysts combined with carbon-based materials in various ways are used to produce hydrogen by electrolysis of water.The MoS₂ have certain HER catalytic activity due to its active sites at the edge of MoS₂,but its poor conductivity greatly limits its large-scale use.Compounding with carbon-based materials can effectively improve the conductivity of the catalyst,and obtain higher HER performance.However,the mechanism of synergy between the active sites of MoS₂ and the carbon substrate is not clear.Revealing the interaction mechanism can provide ideas for the designing of non-noble metal HER catalysts.The carbides and nitrides of element W which is in the same group with Mo in periosic table,have an electronic structure similar to that of Pt and exhibit similar catalytic activity to Pt-like catalysts.Therefore,the development of WC/WN non-noble metal based HER catalysts is expected to replace traditional Pt-based catalyst and further promote the industrialization of hydrogen production.The main research of this paper are as follows:（1）The MoS₂（O）/OMCA composite catalyst was prepared by a three-step method.The few layers of MoS₂（O）nanosheets can be evenly dispersed on the surface of the carbon substrate OMCA,thereby exposing a large number of active sites.In 0.5 M H₂SO₄ solution,the TOF value of MoS₂（O）/OMCA catalyst reached0.067 s^-1,the Tafel slope is 52.3 m V dec^-1 and the stability maintain for 20 h.By adjusting the temperature of heat treatment,the electron-donating ability of the carbon substrate can be effectively adjusted,and the electronic structure of MoS₂（O）can be adjusted.Through the DFT calculation,the synergy mechanism between MoS₂（O）and the carbon substrate can be revealed from the atomic level.（2）The catalysts of different phase components were synthesized by the solution immersion-heat treatment method,respectively W₂N,WC/WN and W₂C.Through the evaluation of HER activity and stability of the catalysts in an alkaline environment(the overpotential at the current density of 10 m A cm^-2 is 232.9 m V and the sability exceeds 10 h),the influence of the phase components on its catalytic performance was studied and the possible mechanism of hydrogen evolution reaction was revealed.