| With the increase of population,people’s demand for energy is increasing.Energy consumption will lead to the excessive emission of greenhouse gases into the atmosphere and damage the atmospheric environment,which has attracted the attention of the entire scientific community.There is urgent need to explore and develop sustainable alternative energy sources to reduce greenhouse gas emissions and replace non-renewable energy.As a clean energy source,hydrogen is considered as an ideal and efficient alternative energy source.Electrocatalytic decomposition of water to produce hydrogen is an efficient,safe and sustainable method for producing high purity hydrogen.Electrochemical water decomposition includes hydrogen evolution reaction（HER）on the cathode and oxygen evolution reaction（OER）on the anode.Among them,the oxygen evolution reaction is a four electron and proton transfer process,which leads to the slow reaction kinetics and greatly limits the reaction rate of electrochemical decomposition of water.At present,Ir/Ru oxide is generally considered as efficient catalysts for OER,but its reserves are small and its cost is high,so it can not be applied on a large scale.Therefore,it is imperative to develop and design non-noble metal electrocatalysts with high efficiency and low cost.A large number of studies have shown that nickel-based sulfides and phosphides have unique electronic structure,good conductivity and low cost,and have great application prospects in electrocatalytic OER.However,nickel-based sulfides and phosphides have the disadvantages of few active centers and poor stability,which greatly limits their application in the OER process.Based on this,the related experiments of nickel-based metal phosphide and sulfide were carried out in this paper.The electronic structure of the catalyst was optimized by heteroatom doping and vacancy engineering strategies adjustment,and its active sites was increased,and its electrocatalytic oxygen evolution performance was deeply studied.The main contents are divided into two aspects as follows:（1）Preparation of Ce-doped Ni2P Nanosheet Catalyst and its Oxygen Evolution PerformanceDesigning non-noble metal electrocatalysts for efficient oxygen evolution（OER）is of great significance for electrochemical energy conversion.Ce-Ni2P/NF was successfully prepared by hydrothermal method and calcination method.Trace cerium doping leads to abundant phosphorus vacancies on the surface of the catalyst,which significantly regulates the electronic structure of the catalyst surface and optimizes the chemical valence state of the catalytic active site.Ce-Ni2P/NF catalyst shows excellent OER performance and long-term stability in alkaline electrolyte due to the adjustment of electronic structure on the surface of the catalyst by cerium doping.Under the current densities of 50 and 100 m A·cm-2,the OER overpotentials of Ce-Ni2P/NF are 241 and 281m V,respectively,which are obviously better than those of Ni2P/NF and commercial Ru O2.At the same time,when Ce-Ni2P/NF is used as the anode and cathode of the fully-dissolved water device,the required voltage is 1.62 V at a current density of 10 m A·cm-2,and the current density is only attenuated by 14.4%after 90 h test at this current density,showing excellent stability.At the current density of 10m A·cm-2,the stability can be maintained for 198 h.The experimental data show that the Ce-Ni2P/NF electrocatalyst has excellent oxygen evolution performance and remarkable stability through coordinated adjustment of heteroatom and vacancy engineering.This work provides a simple synthesis strategy for lanthanide metal doping,and enriches the understanding of lanthanide metal improving the performance of electrocatalyst.（2）Preparation of Fe and Zn Co-doped Ni3S2 and Study on its Oxygen Evolution PerformanceIn the previous work,doping is mainly controlled by one element,but there was little research on polyatomic doping.Therefore,in the third chapter,the OER performance of the catalyst is improved by polyatomic co-doping,and the precursor was loaded on nickel foam with three-dimensional carrier by solvothermal method,and then Ni3S2 nano-plates co-doped with iron and zinc were synthesized by hydrothermal vulcanization.The OER test in alkaline solution shows that when the current density reaches of 100 and 400m A·cm-2 the overpotentials of Fe,Zn-Ni3S2/NF are only 264 and 299 m V,respectively,and the slope of Tafel is only 45.9 m V·dec-1.When the current density is 100 m A·cm-2,the stability can be maintained for 80 h,and the current density shows minimal attenuation.In the total hydrolysis device composed of it,the current density of 10 m A·cm-2 can be driven by a voltage of 1.61 V,and it can run stably for 80 h at this current density,which shows that the material has good total hydrolysis performance and stability.The experimental results show that the doping of Fe and Zn will increase the number of active sites of the catalyst,reduce the resistance of the catalyst,and facilitate the mutual transfer of electrons,thus improving OER activity.This work provides a reference for designing efficient and stable co-doped catalysts.The experimental results show that the doping of Fe and Zn will increase the number of active sites of the catalyst,reduce the resistance of the catalyst,and facilitate the mutual transfer of electrons,thus improving OER activity.This work provides a reference for designing efficient and stable co-doped catalysts. |
