The Preparation Of Carbon-supported Iron-based Electrocatalysts Containing Boron And The Study On Its Water Splitting Performance

At present,the electrocatalytic decomposition process of water is the most prominent of the hydrogen evolution reaction?HER?of the cathode or the oxygen evolution reaction?OER?of the anode.The catalyst is still a noble metal catalyst,such as platinum,rhodium and ruthenium,but high prices and scarce stocks limit large-scale applications.In recent years,a large amount of research has focused on non-expensive transition metals,and great progress has been made,but its catalytic activity is still far behind that of precious metals.Effective regulation of the chemical composition and structure of the catalyst is important to further improve the performance of the electrocatalyst.Based on the idea of design,preparation,structure and composition control of iron-based boron-containing compounds,the following research contents were carried out:?1?The B-Co P/CNT material was prepared by simple chemical reduction and low temperature phosphating.The doping of B can effectively regulate the extranuclear electronic structure of Co and P in Co P.The catalytic activity of B-Co P/CNT is significantly improved compared to Co P/CNT.The current densities of 10 m A cm^-2 in acidic,neutral and alkaline media require 39 m V,79 m V and 56 m V,respectively.It is found by DFT calculation that the hydrogen adsorption Gibbs free energy of B-Co P/CNT is closer to zero than Co P/CNT,indicating that the reaction process is carried out closer to thermal neutrality.?2?Ni₃Fe₂-B_i nanosheets?NS?with high intrinsic catalytic activity were prepared by simple wet chemical in situ reduction synthesis method,and grown on rGO in two-dimensional form of nanosheet/nanosheet.This composite form increases the contact surface between the Ni₃Fe₂-B_i NS and the rGO substrate,more conducive to the transfer of electrons during the catalytic reaction,thereby promoting the reaction kinetics.Finally,due to the high exposure of the surface active sites,enhanced electron transport capabilities,Ni₃Fe₂-B_i NS/rGO electrocatalyst exhibits higher OER catalytic activity than noble metal RuO₂ under alkaline conditions,the overpotential at a current density of 10 m A cm^-2 is only 180 m V.?3?The bifunctional catalyst of FeCo-B_i@Co Fe nanoparticles grown in situ on rGO was successfully prepared by a simple chemical reduction synthesis strategy.The outstanding characteristics of the prepared catalyst are that the structure has abundant heterogeneous nano-interfaces,so that it not only has the advantages of the respective components,but also the FeCo-B_i@Co Fe/rGO heterostructure can play a synergistic effect in the HER and OER processes.The FeCo-B_i@Co Fe/rGO electrocatalyst exhibited the best OER and HER properties compared to the individual components.The potentials of OER and HER were as low as 230 m V and 170 m V,respectively,at a current density of 10 m A cm^-2 in an alkaline electrolyte.Using FeCo-B_i@Co Fe/rGO to construct two-electrode system electrolyzed water,the overpotential at a current density of 10 m A cm^-2 was 1.64 V,which is lower than most of the bifunctional catalysts reported,and can work stably for more than 20 h.