The Construction And Properties Of Adjustable And Efficient Electrocatalyst For Water Splitting Technology

Since the industrial Revolution,the traditional fossil energy has been facing the danger of exhaustion after hundreds of years of extensive use,and the waste generated by the use of fossil energy has also brought about environmental pollution.Hydrogen is seen as a promising energy because of its superior properties,and hydrogen production by electrolysis of water is considered to be an efficient industrial production method.However,the high energy conversion efficiency of electrochemical water cracking requires low cost and high activity electrocatalysts.Traditional precious metal catalysts are not suitable for large-scale industrial use due to their low earth content and high cost.Therefore,researchers are working to develop high performance electrode materials with rich content of transition metal based materials.In addition,to further reduce the cost and complexity of real-world applications,bifunctional catalysts that can be used at both the anode（i.e.,oxygen evolution reaction,OER）and the cathode（i.e.,hydrogen evolution reaction,HER）are economically and technically desirable.Transition metals（such as Fe,Co,Ni,etc.）have advandtages of abundant resources,easy mining,low price,high conductivity and excellent stability,and similar d electronic structure and catalytic ability to platinum,so they show great promising.In this theisis,three kinds of bifunctional transition metal-based catalysts were synthesized by solvothermal and high temperature calcination.Carbon cloth and nickel foam were selected as conductive substrates to improve electrical conductivity of electrode.First,Ni Fe-LDH nanosheets grown on carbon cloth was synthesized by solvothermal method with Fe and Ni metal salts as raw materials.The electronic structure of LDH was modulated by adding a small amount of Ce salt during solvothermal process.Ni Fe Ce_x-P biunctional catalyst was obtained by further phosphating reaction method.Secondly,Ni（OH）₂ nanosheets supported on carbon cloth were synthesized by solvothermal method using Ni metal salt as experimental materials.Then,the hydroxide nanosheets were converted to Ni Fe-MOF by introducing an organic ligand containing Fe by solvothermal method,then the iron phosphide and nickel phosphide hybrid was constructed by phosphating reaction.It retained the nanosheets structure of the precursor;Thirdly,Ni Fe-MOF was synthesized on nickel foam by one-step solvothermal method with 1,1’-sulfonyl diimidazole ligand and Fe and Ni metal salts as raw material.The product show irregular spherical structure.After phosphating,the Ni₉S₈/Fe PO₄ catalyst show aggreageted nanoparticles and sheet structure.The microstructure and composition of the materials were analyzed by SEM,TEM,XRD and XPS.The electrochemical properties,stability and intrinsic activity of the synthesized materials were studied by using CV,LSV,I-T,ADT,EIS,ECSA and other electrochemical test methods.The results showed that the three synthesized materials had good catalytic activity for hydrogen evolution and oxygen evolution.