Synthesis And Electrocatalytic Hydrogen Evolution Of Cobalt Matrix Composites

In recent years,with the development of economy and the progress of the society,the need for energy is increasing.The toxic and harmful gases and dust particles produced during the burning of traditional fossil fuels which have seriously affected people's life and restricted the harmonious and sustainable development of society.Hydrogen energy has attracted a lot of attention due to its advantages of green environment,zero carbon and renewable energy.In the electrochemical process of hydrogen evolution reaction by electrolytic water,there is a difference between positive and negative voltage and thermodynamic response electromotive force,which is called overpotential.The application of hydrogen production by electrolytic water is seriously restricted due to the large overpotential.The traditional Pt,Pd and other noble metal catalysts can effectively reduce the overpotential.The noble metal catalysts have the advantages of high electrocatalytic activity and good stability,but low resource reserves and high price are limited their large-scale promotion in business.Therefore,the preparation of low cost and good catalytic activity catalyst is the focus of the research.Transition metals and their compounds have been widely researched in the hydrogen evolution reaction research because of their inherent electron orbital characteristics.Through the experimental investigation,the electrochemical catalysts can greatly reduce the HER overpotential by the synergistic effect of different metals.Therefore,we have carried out the following two aspects of the research.?1?We designed a method to synthesize CoSe₂/WSe₂/WO₃ hybrid nanowires on carbon cloth substrate.Firstly,the precursor Co-W-O nanowires grown on carbon cloth substrate directly by using a simple hydrothermal method.Then the precursor Co-W-O nanowires were placed in a tube furnace containing selenium powder for selenium treatment,and CoSe₂/WSe₂/WO₃ hybrid nanowires materials were obtained.As hydrogen evolution reaction catalyst,CoSe₂/WSe₂/WO₃ NWs/CC showed a superior catalytic activity.The overpotential only need 115 mV to achiev e the current density of 10 mA cm^-2,and the Tafel slope is lower.After 48 hours of long cycle stability test,the overpotential is only a small change,which shows the good stability of this catalyst.?2?CoMoO₄ nanosheets coated CoO nanowires were prepared on the Ni foam substrate.The Ni foam substrate can enhance the conductivity of the material.Compared with the two-dimensional material,the foam nickel with three-dimensional skeleton structure has a larger specific surface area,which can help to im prove the electrocatalytic activity of the material.The CoO nanowires on nickel foam were prepared by simple hydrothermal method,and then further hydrothermal and high-temperature annealing were processed,the CoMoO₄ nanosheets were successfully prepared on the CoO nanowire.In the end,CoMoO₄ nanosheets coated CoO nanowires composite materials with core shell structure were obtained.In hydrogen evolution reaction,CoO@CoMoO₄ has good electrocatalytic activity.When the current density is 10 mA cm^-2,the overpotential is only 160 mV,and the slope of Tafel is low,the electrochemical activity area is large and the stability is strong.And it has a small Tafel slope,large electrochemical active area and excellent electrochemical stability.