Preparation And Electrocatalytic Oxygen Evolution Performance Of Nickel-iron-based Nanocomposites

The development of low cost and easy to prepare high performance non-noble metal oxygen evolution reaction(OER)electrocatalyst is of great significance for hydrogen production from water electrolysis.Nickel-iron(Ni Fe)-based electrocatalysts,especially(hydroxy)hydroxides,has received widespread attention due to their low price,abundant reserves,and good OER activity.However,such materials have low conductivity,easy aggregation,and poor stability problem.Therefore,the use of effective strategies to control the chemical composition and structure of the catalyst is expected to improve the activity and stability of this type of electrocatalyst.Based on the above considerations,this paper has carried out the following research contents:Using dipotassium hydrogen phosphate as the phosphorus source,ferric nitrate nonahydrate and nickel chloride,the nickel iron phosphate/nickel foam(Ni Fe Pi/NF)composite material was successfully synthesized through a one-step hydrothermal method.Modern characterization techniques such as SEM,TEM and XRD were used to characterize Ni Fe Pi/NF composites,and the effects of different metal ratios,dipotassium hydrogen phosphate input and hydrothermal temperature on the electrocatalytic OER performance of Ni Fe Pi/NF composites were systematically investigated.The results show that the Ni Fe Pi/NF composite material has a sea urchin-like structure.When the current density is 50 m A cm^-2,the Ni Fe Pi/NF composite material only needs overpotential of 230 m V.In addition,the Ni Fe Pi/NF electrocatalyst also performs well stability.Ultra-small nickel iron(hydrogen)oxide nanoparticles/reduced graphene oxide(Ni Fe O NPs/r GO)composite materials were prepared by simple electrostatic assembly and subsequent in-situ reduction reactions,and the electrocatalysis of graphene with different oxidation levels was systematically investigated The impact of OER performance,combined with modern characterization technology to characterize composite materials,and discuss the interaction and reaction mechanism between Ni Fe O NPs and graphene.The results show that the Ni Fe O NPs(Ni Fe O NPs/r GO)OER activity anchored to the r GO is significantly improved,with overpotential of 201m V at 10 m A cm^-2 with a low tafel slope of 68 m V dec^-1 and excellent stability.