Preparation Of Self-Supported Nickel-Based Compound Molybdenum Diselide Array And Its Electrocatalytic Hydrogen Evolution Performance

The traditional highly active catalysts for electrolysis of water through hydrogen evolution reaction（HER）are precious metals（such as Pt,etc.）,but they are too expensive and their earth reserves are small.At present,it is very important to develop low-cost,efficient non-precious metals catalysts with an abundant earth reserve.MoSe₂ is an important transition metal chalcogenides,which has attracted much attention due to its low hydrogen adsorption barrier and high electrochemical activity.However,due to the easy agglomeration and stacking of MoSe₂ nanosheets and their poor electrical conductivity,the application of MoSe₂ in electrocatalysis is hindered.In order to improve the HER performance of MoSe₂,they are good strategies to construct heterostructures or self-supported electrodes by hybridizing MoSe₂ with other materials or conductive substrates.Nickel-based compounds have many advantages of low cost,good electrical conductivity,the abundant reserves and good corrosion resistance,to build heterojunction interface between MoSe₂ and Nickel-based compounds can improve the electrical conductivity of MoSe₂,adjust the electronic structure,increase the active site,improve the mass transfer rate and bring about synergistic effect,enhancing the HER performance.Based on this,this paper will prepare Nickel-based compound-MoSe₂ array on three-dimensional self-supported flexible carbon cloth substrate,and study its HER performance in alkaline solution.The main contents are as follows:（1）The prepared Ni（OH）₂-MoSe₂/CC heterostructure exhibits excellent HER performance:,the overpotential is 130 m V at the current density of 10 m A cm^-2,the Tafel slope is 78.2 m V dec^-1,the electrochemical active area is 807.5 cm²,and the long cycle stability is excellent.At the same time,DFT theoretical calculation proves that Ni（OH）₂ can not only regulate the electronic structure,but also promote the decomposition process of water in Ni（OH）₂-MoSe₂ heterostructure.（2）Using NiMoO₄ nanowires/CC as precursor,and then NiMoO₄ nanowires/CC were selenized by the method of chemical vapor deposition,the NiSe-MoSe₂/CC heterostructure array with abundant defects was prepared,and the effects of selenization time（0.5,1,2,3 h）on the grain size,morphology and electrocatalytic HER performance were discussed.The experimental results show that the material（NiSe-MoSe₂/CC-1 h）generated by selenizing for one hour shows excellent HER performance:,the overpotential is 132.1 m V at the current density of 10 m A cm^-2,the Tafel slope is 86.2 m V dec^-1,and the electrochemical active area is 1032.5 cm².Moreover,it has excellent long cycle stability.（3）NiMoO₄ nanosheets/CC with abundant active sites were prepared as precursors by changing the growth conditions of NiMoO₄.The NiSe₂-MoSe₂/CC composites prepared by hydrothermal selenization had loose porous structure,and compared with Ni（OH）₂-MoSe₂/CC and NiSe₂-MoSe₂/CC composites,its HER performance is greatly improved:,the overpotential is 128 m V at the current density of 10 m A cm^-2,the Tafel slope is 50.2 m V dec^-1,the electrochemical active area is1640 cm²,the charge transfer impedance is small and the long cycle stability is excellent.