Controlled Synthesis Of FeCoNiCuMn High-Entropy Alloy And Its Electrolytic Water Propertiesy

Hydrogen energy is a well-known clean energy source and its development is conducive to alleviating energy problems as well as environmental issues,which is more in line with the goal of sustainable development.Among the many options to prepare hydrogen energy,the electrolysis of water is a more feasible,simple and efficient mean.In order to improve the efficiency of water electrolysis,the use of catalysts is inevitable.However,the commonly used precious metal catalysts today are costly and in low reserves,and there is an urgent need to develop catalytic efficiency and low-cost catalysts to replace the precious metal catalysts.Magnetic elements are abundantly available,and the high entropy alloys composed of magnetic elements show excellent catalytic properties and have good research prospects.In this paper,we mainly focus on FeCoNiCuMn high-entropy alloys to design and synthesize,then study their electrocatalytic properties from two aspects.（1）Fe,Co,Ni,Cu,Mn,Fe Ni Cu,Fe Ni Cu Mn and FeCoNiCuMn high-entropy alloys were sequentially deposited on copper foam substrates by electrodeposition and their water electrolysis performance was studied.All the prepared catalysts have formed face-centered cubic structures,which were uniformly loaded on the copper foam skeleton in the form of particles.The high-entropy alloys were 5 nm-sized particles.The electrochemical results showed that the catalytic performance of Co nanoparticles was much better than that of the other four elements.The performance of the catalyst gradually improves with the addition of elements.Among them,the FeCoNiCuMn high-entropy alloys have a hydrogen evolution reaction overpotential of-190 m V and an oxygen evolution reaction overpotential of 260 m V at a current density of 100 m A cm^-2,which are far superior to single elements and alloy catalysts.The superior performance of the high-entropy alloys is attributed to the reduced particle size forming more active sites and their internal lattice distortion.（2）FeCoNiCuMn high-entropy alloy catalysts were loaded on Cu nanowire arrays,and then investigating the effect of catalyst dispersion on the electrolysis of water.The Fe,Co,Ni,Cu,Mn,Fe Co Ni and FeCoNiCuMn high-entropy alloys were prepared sequentially at 50 m A cm^-2 current densities with deposition times of 7 min and 15 min,respectively.The electrochemical results show that the FeCoNiCuMn high-entropy alloys have a hydrogen evolution reaction overpotential of-173 m V and an oxygen evolution reaction overpotential of 200 m V at a current density of 100 m A cm^-2,and can be operated stably for 30 h with only a trace of decay,which is better than the sample loaded directly on the copper foam skeleton.This is due to the copper nanowire arrays optimizing the dispersion of catalyst and accelerating the electron transfer between electrolyte and catalyst.