The Study Of Preparation Of Molybdenum-based Bimetallic Compound Materials And Their Electrocatalytic Performance

With the increasing energy crisis produced by the development of the world and the growing environmental pollution caused by the large-scale burning of fossil fuels,more and more researchers focus on clean renewable energy.Hydrogen produced by electrochemical methods has become a research hotspot because it is an efficient and clean energy.Platinum-based（Pt）catalysts is recognized as the best electrocatalysts in hydrogen evolution reaction,but its high cost and low content have limited its widespread use.At present,Molybdenum-based transition metal materials are paid more attention by researchers due to their rich chemical state and low cost.This article is based on Co-Mo bimetal oxides to build heterostructure electrocatalyst,which is committed to achieve highly active and durable.CoMoO₄ and Co₃O₄@CoMoO₄ heterostructures were prepared by changing the type of metal salt in the hydrothermal method,and their morphology and structure were characterized by SEM,XRD,BET and TEM,respectively.Electrochemical tests show that the Co₃O₄@CoMoO₄ heterostructure has better hydrogen evolution performance,which is mainly due to the large number of active sites provided by its larger specific surface area.And the unique heterostructure provides extra electron transport channel reduces the impedance of the electrode.The Co-Mo oxide heterostructure Co₃O₄@CoMoO₄/CC prepared in the previous chapter was partially phosphated by controlling the conditions.Due to the difference stability between single-bimetals composite,the CoP@CoMoO₄/CC heterostructure was successfully synthesized.The combination of highly active CoP and highly stable CoMoO₄enables electrode materials to have both high activity and stability.Electrochemical test shows that the overpotential and Tafel slope of CoP@CoMoO₄ have been greatly reduced,and the cycle stability is excellent.After 30 hours of stability test,the potential is only increased by 3.2 m V.The key reason of the little change is from its good morphology and composition stability.CoMoO₄ nanowires were prepared by hydrothermal method,and then reduced by hydrogen to convert CoMoO₄ nanowires into CoMoO₄-Co₂Mo₃O₈ heterostructures in high temperature,the effect of reaction conditions on the final product was also explored.The unique heterostructure was analyzed by SEM and TEM.Electrochemical tests show that the overpotential of the heterostructure CoMoO₄-Co₂Mo₃O₈ is only 57 m V,with a low Tafel slope.It is also very durable in alkaline solution,which is better than most reported metal oxide hydrogen evolution reaction catalyst.The first-principles calculation results show that the CoMoO₄-Co₂Mo₃O₈ heterostructure has the lowest hydrogen adsorption Gibbs free energy and stronger metallicity.