Structure Design And Oxygen Evolution Performance Of NiSe₂

Recently,due to its high energy density,storability,renewability and lack of pollution,hydrogen energy is currently regarded as the best alternative energy source.One of the most appealing methods for obtaining clean fuel from renewable energy sources is commonly recognized as the electrolysis of water to make hydrogen.Troublingly,the barrier of water electrolysis efficiency is mainly the oxygen evolution reaction（OER）at the anode,which requires high overpotential due to multiple proton-coupled electron transfer process resulting in sluggish kinetics.Thus,it is inevitable that high cost performance,high activity,and stable electrocatalyst will be built in order to achieve high efficiency electrolytic water hydrogen generation.Due to their high cost and scarcity,precious metal-based catalysts,which are the most active and effective OER electrocatalysts,have limited use in large-scale industrial applications.Therefore,it is crucial to create suitable non-precious metal catalysts that are abundant and have high activity as replacements.The purpose of this paper is to investigate the effective Ni Se₂ catalyst,which intends to increase the number of active sites,raise the intrinsic activity,and improve electrical conductivity.To that end,we first designed Ni（OH）₂with a nanosheet structure.After that,the array was subjected to hot selenization to study the changes in its morphology and structure and to investigate the causes of the rise in electrical conductivity and the rise in the number of active sites,which accelerated the rate of OER reaction.Even while the performance of OER increased after selenization,it still differed significantly from that of precious metals.In order to further improve the catalytic performance of OER,transition metal element Fe doped Ni Se₂ was utilized to regulate the morphological and electronic structure,further increase electrical conductivity and intrinsic activity.In addition,it overcomes the disadvantage of poor stability in alkaline electrolytes.The following are the specific findings and study findings of this paper:1.Using a one-step hydrothermal process on Carbon Cloth（CC）,Ni（OH）₂ with a smooth nanosheet structure was produced.Through selenization in an argon environment,the Ni Se₂ array with a porous nanosheet structure was created.This rough nanostructure can increase the active surface area and expose more active sites.In addition,the conductivity and intrinsic activity of Ni Se₂ were also improved.The overpotential falls from 409 m V to 331 m V at a current density of 10 m A/cm².2.On the basis of the previous work,Ni Se₂ doped with different proportions of iron was prepared on carbon cloth by hydrothermal treatment and selenization.Fe doping regulates the electronic structure of Ni Se₂,which reduces the Ni²⁺/Ni³⁺ratio.In addition,by calculating the Redox constant（K_S）,it was found that Fe doping increased the adsorption strength of catalyst and OH^-for accelerating OER process.The introduction of Fe also effectively improves the intrinsic activity,facilitates the charge transfer of the material,and reduces the overpotential of the catalyst,resulting in OER catalytic performance of the as-synthesized 20%Fe-Ni Se₂/CC is better than pure Ni Se₂.In 1 M KOH,the as-synthesized 20%Fe-Ni Se₂/CC requires only 221 and 253 m V to be achieved at 10 and 50 m A/cm²,the smaller Tafel slope of 31.8 m V/dec and the retention rate reaches 93%after 24 h stability test.