Research On Controllable Preparation And Performance Of Interfacially Enhanced Ru-based Electrocatalyst

Hydrogen energy is a clean and green energy.Hydrogen production is a key technology in the development of renewable and clean energy economies.Compared with the current industrial methods of steam reforming methane or coal to produce hydrogen,which will cause serious pollution,electrolysis of water is an environmentally friendly method of hydrogen production without emission of pollutants.The process consists of two half reactions,namely hydrogen evolution reaction（HER）and oxygen evolution reaction（OER）.At present,among all electrocatalysts,platinum（Pt）and iridium dioxide（Ir O₂）are still the most active materials for HER and OER.However,due to the scarcity of precious metal resources and high cost,their large-scale commercial applications are limited.Therefore,it is of great significance to seek for high efficiency,low cost and good durability of electrocatalysts to reduce the electrical energy needed for electrocatalytic water decomposition and to maximize the catalytic efficiency.In recent years,it has been found that ruthenium substances（Ru and Ru O₂）have excellent adsorption capacity for hydrogen and oxygen intermediates,and are cheaper than platinum,so they have attracted much attention.However,ruthenium has a strong ability to adsorb hydrogen,which is not conducive to water electrolysis.With proper material design,interface regulation and carrier control,ruthenium-based materials can exhibit similar or even better activity than platinum.Therefore,it is still an arduous challenge to prepare ruthenium-based electrocatalysts with economic,high efficiency and wide application value.In this paper,the ruthenium-based nanomaterials as the main research content,through the design and control of the composition,structure and morphology of the ruthenium-based composite materials,realize the preparation of highly active electrocatalytic materials,and study the alkaline conditions in total water hydrolysis and in a wide range of p H applications in the electrocatalytic hydrogen evolution.The main points could be summarized as follows:（1）We used flexible carbon cloth as the substrate for growth.Firstly,we treated the carbon cloth for different time with O₂^-plasma to adjust the O/C ratio of the surface to regulate the growth of Ni Mo O.On this basis,Ru O₂/Ni Mo O nanowafer-structured bifunctional electrocatalysts were constructed by simple impregnation and annealing processes.By changing the O/C ratio on the surface of the carbon cloth,the geometry of the material can be well controlled,thus providing rich interfaces,active sites and pores for HER and OER,and accelerating the material transfer.The introduction of high-value Mo ions into Ni O can promote the dissociation of water,provide H and O active intermediates for the reaction continuously,and provide interfacial synergy with Ru interface.Therefore,Ru O/Ni Mo O shows excellent water electrolysis performance.In 1M KOH solution,when the current density is 10 m A·cm^-2,the overpotential of HER,OER and fully hydrolyzed water is 37 m V,280 m V and 1.56 V,respectively,showing excellent catalytic activity.The design strategy proposed in this work may provide new ideas for the development of advanced nano hybrid catalysts for other energy storage and conversion applications.（2）Through wet chemical reduction and phosphating treatment,we constructed Ru/Co P/N-GO multifunctional co-catalytic interface catalyst to regulate HER activity in a wide p H range.The introduction of Ru interface can reduce the adsorption of H^*by Co P and make it have nearly zero H^*binding energy.Moreover,Ru/Co P/N-GO catalyst can adsorb H₂O molecules at a faster rate,thus promoting the Volmer process.Nitrogen-doped graphene can improve the electrical conductivity of graphene and increase the material defects to promote the dispersion of nanostructures.The unique d-electron orbitals of transition metals and the possible presence of transition metal-N/C chemical bonds and nitrogen-doped carbonaceous materials can enhance the interaction between the supported graphene and nano-catalysts,thus promoting electrocatalytic activity.The synergistic effect of Ru/Co P/N-GO interface makes it exhibit higher conductivity,the best water adsorption energy and faster charge transfer ability,thus improving the HER activity of Ru/Co P/N-GO.In acidic and alkaline media,35.1 m V and24.8 m V are required to achieve a current density of 10 m A·cm^-2,which is close to the activity of commercial Pt/C catalysts.The results of this study highlight the importance of Interface Engineering in controlling the electronic properties and electrocatalytic activity of metal nanoparticles.