Construction Of High-current-density And High-stability Nickel-based Electrode Material And Exploration On Hydrogen Production By Anion Exchange Membrane Electrolytic Water

The development of low-carbon,clean hydrogen energy is a global consensus.The development of hydrogen production technology by electrolysis of water is a breakthrough for low-carbon,clean hydrogen supply and will be a pivotal field for supporting the new energy development and establishing a hydrogen-electricity synergy pattern in the future.Anion exchange membrane water electrolysis（AEMWE）are considered a promising hydrogen production technology due to its unique advantages of low cost and high efficiency.Anion exchange membrane water electrolyzer is one of three low temperature（<200℃）electrolytic water.AEM is still in development.At present,hydrogen production technology is mainly concentrated in the field of low current density,which is difficult to meet the demand of industrialization.Therefore,the development of high-current-density(>200 m A cm^-2)and stable electrocatalyst for AEMWE is the key to realize green hydrogen production from fundamental research to practical application.At present,lots of precious metal catalysts such as Pt/C,Ir O₂ etc.have been explored and used for hydrogen evolution reaction（HER）and oxygen evolution reaction（OER）.However,due to high cost and the scarcity of precious metals,the commercialization of the precious metal catalysts is greatly hindered.To reduce the preparation cost,the comprehensive water electrolysis catalysts still need to be synthesized from earth-abundant components,and most importantly,to rival the performance of state-of-the-art noble metal-based catalysts.IN terms of water electrolysis,research on the synthesis of various noble metal-free electrocatalysts based on transition metal-containing materials such as Co,Mn,Mo,Ni and Fe has been in-depth explored.So far,Ni-based catalysts have attracted great attention due to their high catalytic activity.In this thesis,two kinds of Ni-based electrocatalysts as the research object were constructed by adjusting the electronic structure and intrinsic activity.The electrocatalytic properties of these materials and their application in electrolysers have been systematically studied.The main contents of these studies are as follows:（1）Ru,W-Ni Se₂ electrocatalyst prepared by a simple two-step hydrothermal method greatly improved the hydrogen evolution performance in alkaline and seawater electrolysis.At 10 m A cm^-2,the overpotential of Ru,W-Ni Se₂ in alkaline and seawater were 100 m V and 353 m V,respectively.Compared with the XPS results of single doped samples,the integration of Ru and W can regulate the electronic structure of Ni Se₂.In situ impedance reveals the possible mechanism of hydrogen evolution and faster reaction kinetics during co-doping.Meanwhile,the ECSA and TOF calculations showed that co-doping strategy is conducive to the exposure of active sites and the enhancement of intrinsic activity.Finally,the results from electrochemical tests and characterization of catalyst after reaction confirmed that Ru,W-Ni Se₂ has a good stability during HER.（2）Ni₃S₄@Ni（OH）₂ shows remarkable HER and OER properties,and also has good catalytic activity at high current density.Ni₃S₄ nanosheet arrays possess the abundant active sites,high conductivity,fast mass transfer and good electron transfer ability,while Ni（OH）₂ has high hydrophilicity,Ni（OH）₂ was electrodeposited onto Ni₃S₄ to afford Ni₃S₄@Ni（OH）₂ composite,which not only improves the hydrophilicity and hydrolytic dissociation ability,but also makes Ni₃S₄@Ni（OH）₂ more stable.Such a Ni₃S₄@Ni（OH）₂ used as anode and cathode material was applied to AEMWE and shows a battery voltage of 1.85/1.96 V at 500/1000 m A cm^-2,saving 0.67 KW·h per cubic meter of hydrogen produced at 100 m A cm^-2 compared to commercial Ni foam electrode.