Synthesis Of 1T MoS₂-based Composite Catalysts And Their Electrocatalytic Hydrogen Evolution

In recent decades,with the development of human life and technology,non-renewable fossil fuels have been consumed on a large scale,and the resulting energy crisis and environmental problems have begun to threaten the survival of human beings.In response to these cases,green and clean new energy has attracted much attention.Hydrogen as a kind of green energy has the advantages of cleanness,high efficiency,stability,abundant reserves and sustainable utilization,is considered to be one of the new energy sources with the most development potential to replace fossil fuels at the moment.Among the many ways of hydrogen production,electrolysis of water to produce hydrogen does not depend on fossil fuels,and is considered to be an efficient and large-scale industrialized way to produce hydrogen.Efficient electrolysis of water for hydrogen production is an important guarantee for its large-scale industrial production.At present,the most effective catalysts are platinum-based precious metal catalysts.However,the reserve of this precious metal is scarce and expensive,which greatly limits the large-scale application of platinum-based catalysts in electrolysis of water for hydrogen production.Therefore,the development of efficient,cheap and stable electrocatalysts for hydrogen evolution is crucial for realizing the industrialization of electrocatalytic hydrogen evolution.In recent years,studies have confirmed that two-dimensional MoS₂ is one of the most potential electrocatalytic materials for hydrogen evolution due to its abundant edge active sites and low cost.Based on above description,in this paper,metal-phase 1T-MoS₂ was grown on carbon paper（CP）by hydrothermal method,which was then used as the substrate to electrodeposit Pt Ni alloy ultrasmall nanoparticles and Co Ni（OH）₂ nanosheets.The electrocatalytic properties of as-prepared CP/1T-MoS₂-Pt Ni and CP/1T-MoS₂-Co Ni（OH）₂ composite catalysts for hydrogen evolution were investigated.The specific research contents are as follows:1.Metal-phase 1T-MoS₂ was firstly grown on the surface of CP by hydrothermal method and then the formed CP/1T-MoS₂ was used as the working electrode to electrodeposit Pt Ni nanoparticles by potentiostatic deposition followed linear sweep voltammetry to construct CP/1T-MoS₂-Pt Ni composite catalyst in three-electrode system.The test of electrocatalytic hydrogen evolution by the prepared CP/1T-MoS₂-Pt Ni composite catalyst show that the overpotential required to reach a current density of 10 m A cm^-2 in 0.5 M H₂SO₄ solution is only 65m V.The CP/1T-MoS₂-Pt Ni composite catalyst gives Tafel slope of 29 m V dec^-1and high stability for hydrogen evolution in acidic solution.The excellent electrocatalytic hydrogen evolution performance of CP/1T-MoS₂-Pt Ni composite catalyst is attributed to the abundant edge active sites of metallic-phase 1T-MoS₂ and the synergistic effect of Pt Ni alloy nanoparticles.This research provides the possibility of designing and developing high-efficiency noble metal alloy catalysts to reduce the use cost of noble metal catalyst for electrocatalytic hydrogen evolution in acidic environments.2.CP/1T-MoS₂ prepared by hydrothermal method was used as a substrate to electrodeposit amorphous Co Ni（OH）₂ nanosheets by potentiostatic deposition in a three-electrode system to construct CP/1T-MoS₂-Co Ni（OH）₂ composite catalyst.Due to the synergistic effect between1T-MoS₂ and amorphous Co Ni（OH）₂,CP/1T-MoS₂-Co Ni（OH）₂ shows excellent electrocatalytic hydrogen production performance in alkaline solution.CP/1T-MoS₂-Co Ni（OH）₂ gives the overpotential of 178 m V at a current density of 10 m A cm^-2 and the Tafel slope of 60.9 m V dec^-1 for electrocatalytic hydrogen evolution in 0.1 M KOH solution.The electrocatalytic hydrogen evolution performance of CP/1T-MoS₂-Co Ni（OH）₂ is even better than that of commercial Pt/C catalysts at overpotential of over 0.190 V and CP/1T-MoS₂-Co Ni（OH）₂ also shows excellent stability.This study overcomes the sluggish electrocatalytic hydrogen evolution kinetics of MoS₂ in alkaline environments.It opens up a new avenue to design a low-cost and excellent non-noble metal electrocatalysts for hydrogen production.In summary,CP/1T-MoS₂-Pt Ni and CP/1T-MoS₂-Co Ni（OH）₂ composite catalysts were synthesized by electrodeposition method using hydrothermally prepared CP/1T-MoS₂ as a substrate.Both of them show excellent electrocatalytic activity and stability for hydrogen evolution in acidic and alkaline solutions,respectively.Our researches reduce the use cost of catalysts and play a positive role in promoting the industrialization of electrocatalytic hydrogen evolution.