Fabrication Of Iron-based Polymetallic Water Oxidation Electrode For Electrocatalytic Oxygen Evolution

Fossil energy is limited and non-renewable as a traditional energy source on the earth.Meanwhile,the burning of fossil fuels will generate a large number of greenhouse gases and some toxic pollutants,which will cause serious environmental pollution problems.Therefore,developing some sustainable and clean energy to replace traditional energy is the most feasible way to solve this problem.Hydrogen as a clean and abundant energy carrier has attracted widespread attention from researchers around the world.Water decomposition reaction is a very important way to produce hydrogen gas.The oxygen evolution reaction?OER?,which includes four proton and four electron transformations together with O-O bond formation,is the basis of water splitting process.Therefore,it is important to develop efficient catalysts to accelerate the OER kinetics and reduce the overpotential associated with this reaction.Early researchers mainly studied single-metal water oxidation catalysts,and a large number of later studies showed that the catalytic ability of single-metal-based water oxidation catalysts was limited.By doping a single metal catalyst with some other metal,the electronic structure of the catalyst can be adjusted and the adsorption energy of the OER intermediate can be reduced.At the same time,there is a certain synergy between different metals in the catalytic process,which can greatly improve the catalytic effect.Based on these backgrounds,in this paper,hydrothermal and electrochemical deposition methods were sequentially used to grow alkaline cobalt carbonate nanowires in situ on a nickel foam substrate and support Fe on the surface of the nanowires to finally obtain Fe-CCH/NF water oxidation electrode.In the electrolyte of 1 M KOH,the electrode exhibits outstanding performance for OER with an overpotential of only 255 mV at a current density of 100 mA/cm²,the slope of tafel curve is 32.1 mV/dec,and it can work steadily for more than 50 h under the current density of 10 mA/cm2.In addition,a simple electrochemical deposition method was used to load CeO₂ and FeOOH water oxidation catalyst on the three-dimensional conductive base nickel foam,and then the required FeP-CeO₂/NF electrode was prepared by calcination in a tube furnace using a high-temperature phosphating method.The electrode exhibits outstanding performance for OER with an overpotential of only 245 mV at a current density of 100 mA/cm²,a Tafel slope as low as 39.1 mV/dec and excellent durability for 50 h at a current density of 10mA/cm² in an alkaline solution.