Study On Controllable Construction And Water Decomposition Performance Of Cerium Modified Nickel-Based Nano-Catalyst

The rapid development of social economy leads to the excessive consumption of fossil energy,which arouses people’s wide attention to the energy crisis and environmental problems.Therefore,the development of efficient,pollution-free green sustainable energy has become an important topic of global concern.Among them,hydrogen is considered as an ideal energy carrier,promising to be an effective alternative to fossil fuels.As an effective way to produce hydrogen energy,water decomposition driven by electricity is one of the most promising methods in the process of realizing renewable and sustainable energy conversion.However,the complex reaction path of electrochemical water decomposition leads to slower reaction kinetics and larger energy consumption,which severely limits its development.Therefore,it is of decisive significance to develop suitable electrocatalysts to drive the reaction.The high price and scarce content of precious metals hinder their widespread application.The development of transition metals with abundant reserves and low prices can effectively solve the above problems.The electron structure,electron transport and electrocatalytic activity can be improved by means of bonding with a conductive substrate,alloying and interface engineering.Based on the above methods,this paper introduces the rare earth metal to modify the material,and realizes the improvement of the electrocatalytic performance of the material by the synergistic effect between different components and the formation of the defect structure.Specific research work is as follows:（1）Due to its abundant oxygen vacancy,CeO₂ as a carrier can improve the electronic structure of the metal surface,which is conducive to electron transport.Therefore,in this paper,rose-like CeO₂ with a special structure was prepared by solvothermal method and high temperature roasting technology,and then Pt-Ni alloy was grown on the surface of CeO₂through solvothermal process to obtain Pt Ni/CeO₂.The rose-shaped structure provides the material with a large specific surface area for better contact with the electrolyte solution,and facilitates the diffusion of gases on the surface of the material.The interaction of the two metals in Pt-Ni alloy can further improve the catalytic performance of the material while reducing the cost.The effect of metal proportion on electrocatalytic performance of Pt-Ni alloy was studied by electrochemical performance test.The results showed that Pt₁Ni₁/CeO₂catalyst showed the best HER activity and catalytic stability,η₁₀=58 m V,and the corresponding Tafel slope is 61.28 m V dec^-1.（2）In order to explore the influence of different carriers on the electrocatalytic properties of materials,Ce modified carbon nanofibers（CeO₂-CNF）were prepared by electrospinning and high temperature carbonization.The carbon fiber has the above advantages of CeO₂,and the introduction of carbon provides higher electrical conductivity for the material.Pt-Ni alloy was successfully loaded on the CeO₂-CNF surface by solvothermal method and the effect of metal proportion on electrocatalytic performance was investigated.Pt₁Ni₁/CeO₂-CNF exhibits the lowest reaction overpotential(η₁₀=37 m V)and rapid reaction kinetics(38.87 m V dec^-1).In addition,the catalyst exhibits superior catalytic stability.（3）On the basis of the above conclusions,CeO₂-CNF was retained as the carrier,and Pt was replaced by Co which had excellent performance in electrocatalyst research.Ni Co-LDH/CeO₂-CNF was obtained by electrodeposition by loading Ni Co-LDH with a nanoflower-like structure on the surface of CeO₂-CNF,which was used as a bifunctional catalyst for water decomposition.The influence of Ni and Co content on the electrocatalytic performance of the material was further studied.The Ni₁Co₂-LDH/CeO₂-CNF composite catalysts showed the highest HER(η₁₀=147 m V)and OER(η₁₀=310 m V)activities,and the corresponding Tafel slopes were 118.10 m V dec^-1 and 66.27 m V dec^-1,respectively.In the above two reactions,the catalysts showed excellent long-term durability.By applying Ni₁Co₂-LDH/CeO₂-CNF in water electrolytic cell,the current density of 10 m A cm^-2 only needs 1.77 V battery voltage.In addition,the catalyst has excellent stability capable of stable operation at 10 m A cm^-2 for 24 h.