Preparation Of Ru-Based Composite Catalyst And Its Properties For Hydrogen Evolution By Electrolytic Water

Due to the shortage of fossil fuels,new energy sources have become the focus of current research.Among them,hydrogen energy has attracted wide attention due to its abundant sources,high energy density and environmental friendliness.Therefore,people need a sustainable and environmentally friendly way to obtain H₂.Hydrogen production from water electrolysis has the advantages of environmental protection and high purity,but it needs an efficient and long-term stable cathode catalyst to promote the reaction.At present,commercial platinum-carbon（Pt/C）,as the reference catalyst for hydrogen evolution reaction（HER）,has excellent catalytic activity due to its moderate Pt-H bond strength,which is conducive to the progress of reaction kinetics.However,Pt,being an expensive and scarce metal,has poor electrochemical stability,which also limits its practical application in large-scale hydrogen production.Ru-H bond and Pt-H bond have similar bond strength,metal Ru has lower price advantage than metal Pt.Therefore,in recent years,Ru-based catalyst as a potential candidate material for hydrogen evolution has been widely concerned by researchers.Based on this,a series of Ru base composite catalysts with high activity and stability were designed by means of cooperative interface and alloying strategies.The contents are as follows:1.A novel Ru Cu-based electrocatalyst（RuCuO_x/NC）is prepared by using cetyltrimethyl ammonium bromide（CTAB）and Ludox as double templates through pyrolysis combined with hot alkali corrosion.RuCuO_x/NC has the same excellent hydrogen evolution activity and stability as Pt/C under alkaline conditions,thanks to the synergistic action of Cu₂₊₁O（with copper excess defect）and Ru.In addition,theoretical calculations demonstrate that the synergistic effect of Cu₂₊₁O and Ru accelerates the H₂O dissociation and reduces the hydrogen adsorption free energy,thus improving the hydrogen precipitation performance.2.In view of the problem that RuCuO_x/NC contains metal oxides and is not suitable for water decomposition under acidic conditions,we further designe a catalyst that can be used as a hydrogen evolution catalyst with wide p H,that is,a porous carbon-supported multi-component composite catalyst（Ru/C）is constructed by simple impregnation-pyrolysis method.Studies have shown that the rich Na Cl in raw materials not only contributes to the dispersion and stability of Ru,but also helps to construct porous carbon skeleton.And alkali Na can also regulate the valence distribution of Ru and contribute to the formation of more active component Ru⁰,thus improving the activity.3.Based on the first two works,we improved the pore-former as a flexible template and synthesised Ru Co/NC composite catalysts in high yields without post-treatment by freeze-drying-pyrolysis.Simultaneously,Ru Co/NC has better hydrogen evolution performance than Ru/NC and Co/NC in a wide p H range,and is even comparable to Pt/C.In addition,the experimental results show that the electron transfer from the Co atom to the Ru atom,and this alloying effect promote the excellent hydrogen evolution performance of Ru Co/NC.