Study On Preparation And Performance Of Non-noble Metal Catalyst For Water Electrolysis

The problems of environmental pollution and energy shortage are becoming more and more serious.It is urgent to develop clean and renewable new energy.Hydrogen energy has been widely concerned because of its advantages of clean,pollution-free,abundant and renewable sources.Water electrolysis is a green method of hydrogen production.When water is electrolysis,the cathode produces hydrogen by reduction reaction,while the anode produces oxygen by oxidation reaction.No pollutants are produced in the process.In the actual reaction,it is necessary to choose suitable catalyst to reduce the overpotential of hydrogen and oxygen evolution,so as to save energy consumption.At present,the best hydrogen evolution catalyst is precious metal Pt,and the oxygen evolution catalyst is Iro₂.However,the characteristics of high cost and low abundance limit the large-scale use of precious metal catalysts.Therefore,the development,preparation innovation and structural design of non-noble metal catalysts with abundant sources and low cost are the research trend at present.First,for hydrogen evolution reaction,an inside-out carburizing method was designed to prepare 2-D Mo₂C.First,carbon layer was coated on the surface of silicon wafer by chemical deposition method,then molybdenum layer was deposited by magnetron sputtering,and then heated in situ carburizing and carbonization.By adjusting the thickness of carbon layer and molybdenum layer molybdenum carbide without carbon deposition can be easily and directly prepared.According to the structural characterization and electrochemical test,compared with the surface carbon-rich Mo₂C,the surface molybdenum-rich Mo₂C showed better hydrogen evolution performance.In the alkaline solution of 1.0 M KOH,the overpotential was only 158 m V when the current density was 10 m A cm^-2.This method overcomes the problem of surface carbon accumulation caused by outer to inner carburizing in traditional methods,and the effect of surface structure of molybdenum carbide on the catalytic performance of hydrogen evolution is investigated for the first time.Secondly,for the oxygen evolution reaction,Co₃O₄nanowire arrays growing on carbon cloth were prepared by one-step hydrothermal method.This three-dimensional structure is conducive to the material transport and gas diffusion in the reaction process.Based on this structure,Fe doping was carried out,which can effectively improve the catalytic performance of Co₃O₄.By controlling the different Fe doping amount to compare and study,it is found that when the ratio of cobalt to iron is 8:1,the catalytic activity of oxygen evolution of the catalyst is the highest.In the alkaline solution of 1.0M KOH,the high current density of 100 m A cm^-2only needs 448 m V overpotential,and has a good stability.