Preparation And Hydrogen Evolution Properties Of Self-supporting Nano-catalytic Electrode Based On Nickel-based Chalcogenide

The strong dependence on fossil fuels not only exacerbates environmental pollution,causes global warming,but also depletes fossil fuels,threatening human energy security.Therefore,the development of a renewable clean energy as a substitute for traditional fossil fuels is an urgent problem.As a renewable fuel,hydrogen has the characteristics of high energy density,large combustion heat value and environment friendly products.It is considered as a potential candidate for future energy supply.In the current common hydrogen production process,hydrogen produced by electrolyzed water has the advantages of high efficiency and low energy consumption,and is expected to become an exemplary technology for large-scale application of hydrogen energy industrialization.However,current electrolysis hydrogen evolution technology is still subject to catalyst constraints.At present,the most active platinum group precious metal catalysts have low reserves and high prices,which limits their large-scale use.Therefore,it is becoming more and more important to find an efficient,low-cost,and stable electrocatalyst.Transition metal compounds have many advantages such as abundant reserves and high catalytic activity,and have become one of the research hotspots.In this paper,Ni-based metal chalcogenide?Ni?S or Se?₂?with pyrite structure was selected as the research object.A series of self-supporting integrated electrolysis hydrogen evolution catalytic electrodes were prepared,by designing and controlling composition of the catalyst surface with the CFP was used as the conductive substrate.The influence of micro-nanostructure and composition control on the activity of catalytic materials was further discussed based on the test of its catalytic properties,so as to provide reference for the further optimization of the performance of catalytic materials.?1?Using carbon fiber paper as the substrate,Ni₂?CO₃??OH?₂ nanowires?NWs?and petal-like nanosheets?NSs?which are nearly perpendicular to the surface of carbon fibers were prepared by hydrothermal method with adjusting the hydrothermal reaction temperature.Then,using Se vapor as Se source,the effects of different heating rate,annealing temperature and reaction atmosphere on the morphology of chemical vapor phase selenization reaction products were studied.NiSe₂ catalysts with three kinds of nano-particles?NPs?,nanowires and nanosheets were prepared.NiSe₂ NWs/CFP has the highest hydrogen evolution catalytic activity by comparing the catalytic performance of the above different morphologies,and only needs an overpotential of 172 mV to provide a current density of 100 mA cm^-2,and the corresponding Tafel slope is as low as 32.44 mV dec^-1.This is due to the fact that NWs have a larger electrochemical active surface area and lower charge transfer resistance than other morphological catalysts?NSs and NPs?,thus ensuring more active sites and faster reaction kinetics.?2?Ni₂?CO₃??OH?₂ nanowires are used as precursors.In the process of chemical vapor deposition,S/Se powder is mixed and ground as a reaction source,and heat is generated to produce S/Se uniform vapor and react with it.The molar ratio of S/Se element was synthesized to synthesize an anion-doped Ni(S_xSe_1-x)₂ nanowire.Ni(S_0.81Se_0.19)₂ nanowires exhibited the best catalytic performance among Ni(S_xSe_1-x)₂ with different compositions through electrochemical tests,The current requires only an overpotential of 93 mV and 135 mV to driving 10 mA cm^-2 and 100 mA cm^-2 and the corresponding Tafel slope is only 42.07 mV dec^-1.This indicates that the activity of the Ni-based metal chalcogenide electrocatalyst can be further improved by anionic doping on the basis of optimizing the surface microstructure,which is of great significance for the development of low-cost,high-efficiency decomposition hydroelectric catalyst.