Surface Engineering Of W（Mo）Te₂ And On-chip Electrocatalytic Properties

W（Mo）Te₂ has excellent electrical conductivity and unique coordination structure,showing high application potential in electrocatalysis field.Therefore,it is vital to develop structural control strategies based on W（Mo）Te₂ to optimize hydrogen evolution performance.Traditional electrocatalytic tests are difficult to accurately determine the properties of different surface structures,which are usually the composite properties of multiple particles.In this dissertation,surface treatment strategies such as plasma treatment and laser irradiation were developed to achieve the precise construction of atomic doping and vacancy on the surface of a single W（Mo）Te₂ nanosheet.The electrocatalytic performance was tested by on-chip electrocatalytic microdevice,which can eliminate the interference of different surface microstructures,and reveal the regulation law of surface structure on the performance.1T’-WTe₂ sheet-based electrocatalytic micro device was fabricated with a single nanosheet as catalyst.The in-situ doping of fluoride ions on WTe₂ nanosheet was achieved by SF₆ plasma treatment.The experiment results showed that the overpotential decreased from0.45 V to 0.27 V after F doping,and the Tafel slope also decreased from 238 mV dec^-1 to 173mV dec^-1,indicating that the surface doping of F could effectively improve the electrocatalytic performance of WTe₂.The interlaminar and in-plane resistance and the surface work function of the nanosheets were also reduced,thus promoting the transfer of electrons.Theoretical simulation revealed that the open coordination environment and the local charge enrichment induced by the doped F promoted the adsorption of proton hydrogen.Te vacancy was introduced into the 2H-MoTe₂ plane by laser irradiation,the electrocatalytic performance of 2H-MoTe₂ basal plane was directly tested by on-chip microdevice.The results showed that the introduction of Te vacancy could significantly improve the catalytic performance of the in-plane site of MoTe₂.The in-situ electric transport tests showed that the carrier mobility is significantly increased and the surface work function is reduced,accelerating the electron transfer in the catalytic process.The theoretical calculation recealed that Te vacancy introduced the defect level,reduced the band gap and improved the conductivity.The electron delocalization around Moatom activated the basal plane site of MoTe₂ and shift the center of the d band,benefiting the adsorption of H on the surface of the catalyst,thus promoting the catalytic reaction.