Study On Electrocatalytic Hydrogen/Oxygen Evolution Reaction Of Transition Metal Sulfide Supported On Nickel Foam

With the rapid consumption of fossil fuels,we are facing crises such as energy depletion,environmental pollution,and climate change,which force us to develop efficient energy storage and conversion technologies.The development of high-performance electrocatalysts is crucial for these clean energy conversion technologies.Hydrogen Evolution Reaction（HER）and Oxygen Evolution Reaction（OER）are key processes in these technologies,both of which involve multi-step electron transfer.A large reaction potential barrier can lead to high overpotential and low energy utilization.So far,platinum based precious metals are recognized as the catalytic materials with the highest efficiency of HER,and iridium and ruthenium based precious metal oxide catalytic materials have also been widely used in OER catalysts.However,due to their scarcity in the crust,high prices,and poor charge discharge stability,these precious metals hinder their large-scale commercial application.Therefore,in recent years,more and more people have been striving to develop rich,efficient,and durable non precious metal electrocatalysts.Nickel foam（NF）is a functional metal material with three-dimensional network structure,large pores and interconnected metal skeleton.This kind of material has a large electrochemical reaction interface,and has a great application prospect as an electrode material for electrochemical hydrogen and oxygen evolution.In view of this,foam nickel was used as the substrate to design and synthesize foam nickel self supporting polymetallic catalyst,and its electrocatalytic performance was studied.The specific research content is as follows:（1）Heterostructure electrocatalyst Sn Fe_nS_xO_y/NF was synthesized on foam nickel substrate by a simple one-step solvothermal synthesis method using thiourea as sulfur source and anchored on foam nickel substrate.The optimum reaction conditions were determined by optimizing the proportion of metal Fe and Sn,different heating temperatures and constant temperature time.At 180℃,Sn Fe S_xO_y/NF synthesized at constant temperature of 180 min at the molar ratio of metal Fe,Sn and thiourea of 1:1:1.75 has excellent catalytic activity and strong stability for oxygen evolution.For HER at 10,100,500 and 1000 m A cm^-2,Sn Fe S_xO_y/NF showed a low overvoltage of 85,167,249 and 324m V respectively,while for OER at 100 m A cm^-2,the low overvoltage was only 281 m V.When it is used as both anode and cathode to assemble an electrolytic cell,the battery voltage is only 1.69V at 50 m A cm^-2.（2）On the basis of（1）preparation of electrocatalyst,excellent Sn Fe Co_0.2S_xO_y/NF active OER electrocatalyst was prepared by doping Co metal elements.The morphology,elemental characterization,electrochemical performance and stability of the prepared ternary metal sulfide Sn Fe Co_0.2S_xO_y/NF were tested.For electrocatalytic OER,at 1.0 mol L^-1KOH solution,only 187 mV and 219 mV overvoltage is required to reach the current density of 10 mA cm^-2and 100 mA cm^-2.