Study On Preparation Of Fe/S Regulated Ni-W-Mo Electrode And Its Performance In Alkaline Water Electrolysis

The environmental pollution caused by the rapid consumption of traditional fossil fuels and the energy crisis caused by the ever-increasing energy demand are the two major problems that plague our development.Hydrogen energy has the advantages of abundant raw materials,high mass-to-energy ratio,storability,and environmental friendliness and regeneration,which make hydrogen energy an effective substitute for fossil fuels.Hydrogen production from water electrolysis is a clean and efficient hydrogen production technology.In the hydrogen evolution reaction,efficient catalysts can effectively reduce the overpotential of hydrogen evolution during the reaction,thereby saving costs.Although platinum and platinum-based noble metal electrodes have excellent hydrogen evolution performance,their reserves are scarce and expensive,which seriously restricts their large-scale industrial applications.Ni-W-Mo alloy electrodes have attracted extensive attention of researchers due to their good hydrogen evolution performance and corrosion resistance.However,their catalytic performance is still far behind that of noble metal platinum,and it still faces less electrocatalytic performance.Problems such as chemically reactive active sites and slow electrochemical reaction kinetics limit its commercial application.In this paper,the microstructure and surface state of Ni-W-Mo electrode materials were regulated by iron/sulfur doping,and the mechanism of the influence of the microstructure and surface state of these electrode materials on their electrochemical properties was explored,aiming to improve the catalytic hydrogen evolution performance of the electrode is expected to achieve the purpose of high efficiency and low energy consumption for hydrogen evolution under alkaline conditions.The main research contents and conclusions are as follows:（1）Ni-Fe-W-Mo novel bifunctional electrocatalysts were prepared on the surface of nickel mesh by galvanostatic electrodeposition.The surface of the as-synthesized Ni-Fe-W-Mo electrode exhibits a dispersed bulk flake-like morphology,and irregular spherical protrusions grow on the flake-like structure.Electrochemical tests found that when driving a current density of 10 m A·cm^-2 in an alkaline medium,the required overpotentials at the cathode and anode ends of the Ni-Fe-W-Mo electrode were 151 m V and 152 m V,respectively.Compared with the Ni-W-Mo electrode,its hydrogen evolution overpotential is reduced by about 18.8%,the number of active sites n is increased by 22.3%,the electrochemical active surface area is increased by 18.3%.The test shows that the oxygen evolution overpotential decay rate of Ni-Fe-W-Mo electrode is lower than1%after 6000 cycles,indicating that the electrode has good evolution.Oxygen long-term stability.The good performance of the bifunctional Ni-Fe-W-Mo electrode can be attributed to the introduction of Fe element,which can greatly accelerate the charge transfer kinetics,and the deep synergy of bisite Ni/Fe can be beneficial to confine more charges to Ni/Fe.On the Fe site,the composite desorption step of atomic hydrogen is accelerated,and the reaction speed of electrolyzed water is accelerated.（2）Ni-S-W-Mo hydrogen evolution electrode was synthesized on the surface of nickel foam by galvanostatic electrodeposition.It was found by SEM and other methods that the surface of the Ni-S-W-Mo electrocatalyst formed a relatively rough nano-spherical particle deposition layer.Compared with the control electrodes Ni-S and Ni-S-W,the chemically active surface area ECSA was increased by 51%and 33%,respectively,indicating that the exposed area of the nanostructures on the surface of the Ni-S-W-Mo electrode was increased.When the current density is 10m A·cm^-2,the hydrogen evolution overpotential of Ni-S-W-Mo electrode in 1.0 M KOH is 76 m V,which is 110 m V and 75 m V lower than that of Ni-W-Mo and Ni-Fe-W-Mo electrodes,respectively.During the HER process,the Tafel slope is 125.7 m V·dec^-1,which follows the Volmer-Heyrovsky mechanism.In the Ni-S-W-Mo electrode,the highly electronegative S absorbs electrons from the metal site and becomes an active site for stabilizing the reaction intermediate.At the same time,the active material Ni₃S₂ forms an amorphous structure suitable for proton binding and electron transfer,which accelerates the electrode The speed of charge transfer within the electrode accelerates the accumulation of electrons on the S atoms,which improves the catalytic activity of the electrode for hydrogen evolution.36 Figures,17 Tables,150 References...