Study On The Preparation And Hydrogen Production Performance Of Metallic Phase MoS₂ Composite Materials

Hydrogen energy is a kind of clean energy with higher energy density and without other by-products such as carbon dioxide after combustion,which is the primal new energy fuel at present.Photocatalytic water splitting and electrochemical water splitting are considered to be the most ideal hydrogen production methods to product high purity hydrogen.For photocatalytic hydrogen production,the band gap and recombination efficiency of electron-hole pairs will limit the hydrogen production efficiency.Therefore,designing a semiconductor photocatalyst with an adjustable band gap,inhibit the recombination of photo-generated electron-hole pairs to develop photocatalytic hydrogen production technology.For electrochemical water splitting,the slow kinetic process and the large overpotential seriously limit the electrocatalytic reaction efficiency.Although the precious metal Pt and its compounds have ideal hydrogen adsorption Gibbs free energy,but the high cost and scarcity,poor stability and low sensitivity to cross-effects limit its industrial applications.Therefore,we should deeply understand the kinetics of different catalytic reactions and the properties of active sites in order to develop electrocatalysts with high activity,low cost and strong stability.MoS₂,especially the metal phase MoS₂(1T MoS₂),as the sheet structure,the base and edge position all shows a large number of active sites.The carrier mobility and the number of active sites is much higher than the semiconductor phase MoS₂(2H MoS₂).These active sites not only have catalytic activity,but also provide an attachment point for the nucleation of atoms,which is conducive to the nucleation of nanoparticle catalysts.Therefore,they are often used as substrate materials to adjust different nanoparticles by changing the reaction conditions.Therefore,metal-based nanocomposites constructed on the basis of 1T MoS₂ have important application prospects in the fields of electrocatalytic hydrogen production and photocatalytic hydrogen production.This article takes MoS₂ as the research object,and conducts research on its material design,preparation,performance testing,and application.The specific research contents and conclusions are as follows:1.1T MoS₂ was prepared through ultrasonicated with 2H MoS₂ in salt solution.Then,1T MoS₂/Cu₂O heterostructure was designed with 1T MoS₂ as substrate and Cu₂O as semiconductor material.Under the action of 1T MoS₂ substrate,we synthesized the Cu₂O nanoparticles with the size of 15 nm by changing the reaction conditions,which increases the specific surface area of semiconductor materials.As a result,the photocatalytic effect of the Cu₂O is greatly improved.Furthermore,the excellent conductivity of 1T MoS₂ accelerates the rapid transfer of electrons and reduces the efficiency of electron-hole recombination.The existence of 1T MoS₂ also reduces the band gap of the Cu₂O to some extent,increases the utilization rate of sunlight,and improves the catalytic performance of the material.This also provides a new idea for the design of photocatalytic semiconductor materials.2.The catalyst of 1T MoS₂/Ru was synthesized by in-situ synthesis.Through electrochemical test results,the overpotential of the catalyst is 89 m V and the corresponding Tafel slope is 41 m V dec^-1.The catalytic performance of 1T MoS₂/Ru compared with the current research status of electrocatalysis is better.Then the morphology of 1T MoS₂/Ru was characterized by SEM and TEM,the element information in the composite material was characterized by XPS and other characterization methods.The research results show that 1T MoS₂/Ru composite material greatly improves the electrocatalytic hydrogen evolution performance of the material,and analyzes the synergistic effect between 1T MoS₂ nanosheets and Ru nanoclusters from the mechanism.