Preparation Of Ru-MoS₂ And Conductive Carrier Composites And Their Electrocatalytic Hydrogen Evolution Properties

In recent years,with the gradual increase of energy demand and the gradual depletion of fossil fuels,it is urgent to develop green and clean renewable energy.Hydrogen energy has attracted wide attention because of its advantages of high calorific value,easy production and no pollution.Electrolysis of water for hydrogen production is a green and sustainable strategy.However,due to the high cost and low reserves of platinum-based catalysts with excellent catalytic performance in water electrolysis hydrogen production,the development of water electrolysis hydrogen production is limited.Layered MoS₂nanosheets are considered to be one of the potential substitutes for platinum-based catalysts because of their low preparation cost and unique electronic structure,especially their better hydrogen adsorption free energy at the edge.However,MoS₂has some problems such as base inertness and poor electrical conductivity,so it is necessary to modify its structure by doping or recombination to improve its catalytic activity and stability of hydrogen evolution.Therefore,in view of MoS₂less active sites and poor conductivity and other problems,this paper goals to start with the reasonable catalyst structure design,vertical growth of MoS₂nanosheets on the conductive carrier,exposing more edge positions at the same time to increase the conductivity of MoS₂,in addition,through metal doping activation of MoS₂inert base surface,increase the active site of the catalyst,Thus,Ru-MoS₂@NC and Ru-MoS₂@PPy catalysts for electrolytic water hydrogen evolution were equipped.The major research contents and conclusions are as follows:（1）Hollow carbon nanospheres（NC）were prepared by hard template method.With the help of Ru metal,MoS₂was uniformly grown on the surface of NC by hydrothermal method,and Ru-MoS₂@NC composite catalytic material was prepared.It was found that Ru could not only induce the transformation of 2H-MoS₂into 1T-MoS₂but also assist the vertical growth of MoS₂on the NC surface to be denser and the size of about 40 nm nanosheets,generating more active sites and improving the catalytic activity.When the content of Ru was 3.39 wt%,the prepared Ru-MoS₂@NC showed excellent hydroelectrolysis activity in 1.0 M KOH solution,with an overpotential of 78 m V at 10 m A cm^-2.Compared with the overpotential（362 m V）of pure MoS₂.（2）Firstly,hollow MoS₂@PPy nanowires were prepared by in-situ restriction growth method using thiourea as sulfur source and Mo O₃core in Mo O₃@PPy as molybdenum source.Then Ru was loaded onto the surface of MoS₂nanosheets by the high-gravity method.MoS₂nanosheets grow vertically on the surface of the PPy layer from inside to outside.This growth type is verified by X-ray photoelectron spectroscopy to effectively strengthen the interaction between MoS₂and PPy,and can effectively prevent the agglomeration of MoS₂nanosheets in the electrocatalytic process.Therefore,the catalytic material with this structure shows good electrocatalytic stability and activity.It not only shows a low overpotential of 39 m V at 10 m A cm^-2,but also shows excellent electrocatalytic stability after 40000 cycles of voltammetry test.Compared with Ru-MoS₂catalyst prepared by beaker impregnation method,the catalytic activity and stability of the material have been effectively improved.