Electrochemical Properties Of MoTe₂ Films Synthesized By Chemical Vapor Synthesis

The requirement and consumption of modern society for energy enables the urgentexploit of renewable energy.Electrochemical hydrogen evolution is an important means of clean and renewable energy,attracting much more research interests.In the electrochemical hydrogen evolution reaction,although the traditional noble metals exhibit excellent performance,their expensive price,low earth abundance and easy pollution make them unable to be used for mass production.Recently,two-dimensional materials?2D?show great potential for electrochemical hydrogen evolution due to their special structure and the unique physical and chemical properties.Currently,most of the research focuses on molybdenum disulfide?MoS₂?,which exhibit good electrocatalytic performance.As a sulfur compound of the same group of molybdenum disulfide,molybdenum telluride?MoTe₂?,which possesses a similar crystalline structure with molybdenum disulfide,also shows good potential for their electrochemical hydrogen evolution application.In this thesis,we systematically investigated the electrochemical hydrogen evolution properties of tellurium molybdenum thin film synthesized by chemical vapor deposition:?1?By controlling the reaction condition in the CVD process,different crystalline phases of MoTe₂ films have been synthesized,including the pure 1T'MoTe₂ film,the mixed 1T'/2H phase MoTe₂ thin film,the mixed Te/1T'MoTe₂ thin film,and their electrochemical properties have been systematically investigated.We found the mixed Te/1T'MoTe₂ thin film shows the best electrocatalytic performance.When the current is 10mA/cm²,the potential is-427mV,but suffered from poor stability.Compared with semiconducting 2H MoTe₂ film,pure 1T'MoTe₂ film shows better electrocatalytic performance due to the high conductivity,when the current is 10mA/cm²,the potential is-553mV with a good stability;?2?The post-treatment under different atmospheres and different temperature were performed to further improve the electrocatalytic performance of 1T'MoTe₂ film.Compared with N₂ atmosphere annealing,The reduced hydrogen atmosphere annealing significantly improve the electrocatalytic performance.When the current is 10mA/cm²,the corresponding potential decreases from-597mV to-427mV with a change of 170mV,and the maximum current increase from 10mA/cm² to 66mA/cm² at potential of-600mV,which is infinitely higher.