Synthesis And Electrocatalytic Hydrogen Evolution Performance Of Two-Dimensional Transition Metal Dichalcogenides

With the increasing consumption of traditional fossil energy prompts people to explore new energy.As a kind of secondary energy with wide sources,clean carbon free,and abundant applications,hydrogen has attracted wide attention all over the world.Hydrogen production from water electrolysis is a key technology to produce hydrogen energy,which can achieve zero carbon emissions and greatly reduce the cost of hydrogen production.However,the dependence on precious metal catalyst greatly limit the popularization of water electrolysis technology in the domestic hydrogen energy market.Therefore,to realize the large-scale promotion of water electrolysis technology,it is the key to develop noble metal catalyst with high utilization rate and non-noble metal catalyst with high activity.Two-dimensional（2D）materials have potential application in catalysis,due to their large specific surface area,superior mechanical properties,and unique physicochemical properties.In this paper,2D transition metal dichalcogenides（TMDs）were used as study object.The preparation methods and performance control strategies of TMDs catalysts were explored.Based on the improvement of the utilization rate of noble metal catalyst and development of non-noble metal catalysts,the mechanism of enhancing the performance of TMDs-based catalysts was discussed.The specific research contents are as follows:Precious metals and their compounds are the main catalyst materials for commercial promotion at present.However,as rare metals,the high price limits the large-scale application.In order to improve the utilization rate of precious metals in TMDs,the effect of lithiation on hydrogen evolution reaction（HER）performance of IrTe₂catalyst was investigated by using the strategy of liquid ammonia assisted lithium（LAAL）.The morphology of IrTe₂was regulated and the intrinsic activity of IrTe₂was optimized by designing the ratio of ammonia lithium.The results of structural and electrochemical characterization showed that LAAL could reduce the size of IrTe₂,while induce the amorphous structure,which effectively improved HER performance.The overpotential of IrTe₂at the current density of 10 m A cm^-2decreased from 176.8 m V to 33.3 m V.In addition to improving the utilization rate of precious metals,the development of non-precious metals is also part of the effort.As a physical field control strategy,light field drive is helpful to improve the performance of catalysts.In this paper,Mo doping Re Se₂achieves the double enhancement effect of catalytic activity and broad solar spectral response.Structural characterization and theoretical calculation（DFT）were used to demonstrate that Mo doping can effectively regulate the electronic structure and band structure of Re Se₂,which promoted the active site and ensure the efficient utilization of thermal electrons.When the Mo doping ratio is 6%,the overpotential of Re Se₂at the current density of 10 m A cm^-2decreases from 239 m V to 174 m V.Under the AM 1.5 sunlight condition,HER overpotential further decreased to 137 m V.Improving the intrinsic activity of non-noble metal catalysts has always been the direction of researchers.In view of the poor activity of the basal plane of metal phosphorus trichalcogenides（MPCh₃）catalysts,we developed a high-entropy regulation strategy to satisfy the needs of high-performance MPCh₃catalysts.Combining advantages of high-entropy alloys（HEAs）for widely regulated electronic structures and abundant element combinations with 2D materials for large specific surface area,a series of 2D high-entropy MPCh₃catalysts were designed and synthesized.By structural characterization and DFT calculation,it was proved that the random distribution of multiple metals in high-entropy MPCh₃resulted in charge rearrangement,which optimized HER performance.Co_0.6（VMnNiZn）_0.4PS₃nanosheets have an overpotential of 65.9 m V at the current density of 10 m A cm^-2,which is one of the best MPCh₃catalysts.