Preparation Of Nickel/Iron-based Phosphide Porous Nanofibers As Efficient Oxygen Evolution Reaction Electrocatalysts

With the rapid development of industry and population,the increasing energy demand has become a major global challenge.Hydrogen is recognized as the most promising energy carrier because of its high energy density and zero carbon emissions.Among various methods of hydrogen production,electrolysis of water has drawn great attention due to its high efficiency and non-pollution.However,the anodic oxygen evolution reaction（OER）exhibits sluggish kinetics resulted from its four-electron transfer process,which becomes the bottleneck for the application.Currently,precious metals,such as Ru O₂and Ir O₂,have high OER activity.However,the scarcity and high price of precious metals hinder their large-scale applications.Therefore,it is urgent to find cheap and efficient electrocatalysts that can replace noble metals.Among various transition metal based electrocatalysts,Ni/Fe-based materials,especially their phosphides,have demonstrated great potential as one of the most promising OER electrocatalyst due to their environmental friendliness,low cost,and abundant reserves.However,their OER are still unsatisfactory,which caused by the improper adsorption capability for different oxygen-containing intermediates during OER process.Based on this,the research contents of this paper are as follows:1.Fe-doped Ni₂P（Fe-Ni₂P）porous nanofibers were prepared by electrostatic spinning together with latter oxidation and phosphorization.Benefiting from the abundant and uniformly distributed active sites,optimized electronic structure,high conductivity,and enhanced mass diffusion rates,the obtained Fe-Ni₂P porous nanofibers exhibited high OER activity and robust stability.Theoretical calculations demonstrated that the interaction between Fe-Ni₂P and the in-situ formed Fe-Ni OOH can improve the adsorption capacity of active intermediates and enhance the electron conductivity,further boosting the OER activity.2.Ni doped Fe P/carbon（Ni-Fe P/C）porous nanofibers were fabricated by utilization the hydrolytic instability of metal-orrganic framework compounds.The synergistic effect brought by the unique one-dimesional porous structure,incorporcation of Ni and coating of carbon can expose more active sites,optimize the adsorption capability for oxygen-containing intermediates and enhance the electronic conductivity,thereby,leading to improved OER activity.The optimal Ni-Fe P/C porous nanofibers possessed a high OER activity,requiring a low overpotential of 256 m V at 10 m A cm^-2in an alkaline solution.Moreover,this catalyst shows great cycling stability--no degradation occurs after 25-hour working.