Preparation Of Transition Metal Matrix Composites And Study Of Their Water Electrolysis Performanc

Overall,the global economy is in a stage of rapid development,the demand for energy is only increasing,and the fossil fuels（coal,oil and natural gas,etc.）as the main energy support are gradually exhausted,and the environmental problems can not be ignored,so we are encouraged to develop renewable clean energy.At present,the clean energy that can be explored includes wind energy,solar energy,hydrogen energy,etc.,among which hydrogen energy stands out due to its high energy density.Among various hydrogen production methods,electrochemical water decomposition hydrogen production technology is considered to be one of the most potential approaches.Hydrogen evolution reaction（HER）and oxygen evolution reaction（OER）are the two half reactions that make up the electrolytic water reaction.Due to the slow kinetics of OER,large working voltage is needed to drive the reaction,which becomes the bottleneck of electrochemical water decomposition technology.To address this challenge,precious metal Pt-based catalysts are widely used as HER electrocatalysts,while precious metal IR-based catalysts such as Ir O₂ are widely used for benchmarking OER activity due to their high activity and excellent durability.However,the high cost and low surface content of precious metals greatly restrict their application in industry,so the cheap and abundant transition metals are favored.This paper discusses how to design and develop an efficient transition metal composite catalyst for electrochemical water decomposition.The specific research content of this paper is as follows:1.NiFeMo trimetallic sulfide electrocatalyst for overall water splitting:The target catalyst Mo Ni Fe S_x@Fe Ni₃ was obtained by two steps hydrothermal method and one step high temperature vulcanization method.The innovation of this work is the induction of three-dimensional Fe Ni₃ foam-supported transition metal sulfides（TMS）,in which Mo nanoparticles are grounded on a nanosheet array of nickel-iron bilayer hydroxides.Thanks to the stable three-dimensional skeleton provided by Fe Ni₃ foam,excellent electronic structure and effective phase cooperation in polyphase TMS,the catalysts Mo Ni Fe S_x@Fe Ni₃ require only 67 m V and 142 m V overpotential to drive the current density of 10 m A cm^-2 in alkaline electrolyte,respectively.HER and UOR properties of the catalyst have excellent performance in neutral electrolyte.This work provides a feasible strategy for preparing bifunctional trimetallic polyphase electrocatalysts for water electrolysis.2.Bifunctional keel flower-like multi-component electrocatalysts for overall water splitting:The final product of the double-function keel-flower multicomponent oxide electrocatalyst Ni Co VO_x@NF was obtained by two steps hydrothermal method and one step high temperature oxidation method.The three-dimensional structure of keel flower increases the active surface area of catalyst,which is conducive to exposing more active sites.At the same time Ni Co VO_x@NF electrocatalyst has an efficient electronic pathway,greatly enhance the ability of electron transmission.The electrochemical properties of HER and OER require only 107 and 217 m V overpotential respectively to drive the current densities of 10 and 50 m A cm^-2.This study provides a feasible heteroatomic doping route for obtaining bifunctional catalysts with excellent water electrolytic properties.