In-situ NiFeLDH Supported On Nickel-foam-based Composite And Its Electrocatalytic Performance Of Oxygen Evolution

Hydrolysis of oxygen production reaction is a four-electron reaction,and it has a higher energy barrier than hydrogen evolution reaction.Hence,the whole process of water electrolysis,oxygen evolution reaction（OER）becomes the dominant step.For the above reasons,the development of a cheap,stable and high catalytic activity OER electrocatalyst in various countries is essential for the practical application of water decomposition.In recent years,Ni Fe Layered Double Hydroxides（NiFeLDH）has become a potential electrocatalytic catalyst for oxygen evolution due to its special sheet-structured and high electrocatalytic activity of hydroxide itself.However,the conductivity of NiFeLDH showed low,so it needs to use other conductive carriers to the electrocatalytic activity of NiFeLDH.In order to solve the above problems,sheet-structured NiFeLDH was grown on the nickel foam by hydrothermal method.In this paper,the specific contents are as follows:（1）The nanosheets-structured nickel-ferrite were grown on nickel foam through hydrothermal reaction.The structure of nickel-ferrite with the highest electrocatalytic activity was found by adjusting the adding proportion of nickel to iron.The nickel-ferric dihydroxides grown on the nickel foam had larger specific surface area and could expose more active sites,and the nickel foam as a conductive substrate could improve the electron transfer ability of the material.The results of electrochemical test showed that at 50 m A·cm^-2,compared with the nickel foam（330 m V）without nickel hot metal talc,the nanosheet of nickel hot metal talc（255m V）shows higher electrocatalytic activity,and has strong stability to OER in 1 M potassium hydroxide electrolyte.The results showed that the nickel foam loaded with NiFeLDH nanosheets has better performance of electrocatalytic oxygen evolution.（2）Ni Fe(OHx)S_y@NF composite material was formed by hydrothermal reaction of Ni Fe（OH）_xS_y@NF nanosheets with Ni-based NiFeLDH as the precursor and Na₂S as the sulfur source.The surface vulcanized nickel foam has better conductivity,which makes charge transfer easier and plays a positive role in enhancing its electrocatalytic activity.The addition of S^2-can regulate the electronic structure on the surface of NiFeLDH and improve its ability to adsorb oxygen.Due to its amorphous structure and more exposed active sites than NiFeLDH,it is a promising electrocatalyst for OER.Therefore,we designed and synthesized Ni Fe（OH）_xS_ycomposite nanosheets supported by nickel foam.According to the electrochemical test,Ni Fe（OH）_xS_y@NF has a better electrocatalytic activity and a lower Tafel slope（70 m V/dec）when the current density reaches 50 m A·cm^-2in the 1 M KOH electrolyte.All these fully indicate that the Ni Fe（OH）_xS_y@NF obtained after vulcanization has better electrocatalytic oxygen evolution activity.