Study On Synthesis And Electrocatalysis Properties Of Nickel Selenide

In order to meet the needs of industrial production,and solve environmental pollution,greenhouse effect and other issues,water-splitting reaction as a new type of hydrogen production,has been widely concerned by researchers.However,the commercial cost of electrolyzed hydrogen production is high and the energy consumption is large.Therefore,the development of a low-cost,high-performance electrolyzed water catalyst has become a research trend in recent years.Low-cost and rich transition metal chalcogenides have achieved unprecedented development in the field of electrolyzed water.Ni and Fe in transition metals are the first choice for research based on price and reserve abundance.Compared with Fe,Ni is in the same family as the precious metal Pt.It has similar properties and potential in theory.The selenium compound with higher conductivity in the chalcogen element.It is more favorable for the adsorption and dissociation of H atom in the electrolysis water reaction than the telluride compound.In general,the method of improving the electrocatalytic hydrogen evolution of materials is to expose more catalytic active sites,improve the conductivity of optimize the adsorption/dissociation energy barrier,and so on.In this thesis,the simple and efficient hydrothermal method is used as the fundamental method.the NiSe₂ system is used to improve the performance of electrolyzed water by means of doping,structure optimization and substrate loading.The specific content includes:1.NiSe₂ nanoparticles were prepared by the method of disproportionation of selenium powder by NaOH and hydrothermal method.At the same time,doped by Fe³⁺ion to enhance the hydrogen evolution performance of NiSe₂.When the doping concentration of Fe³⁺ion is10 mol%,the prepared catalyst has the best electrolyzed water performance.It has 200 mV the overpotential at the current density of 10 mA cm^-2,and 30.9 mV dec^-1 the tafel slope,which is close to commercial platinum carbon.2.NiSe₂ nanowires were successfully prepared by using Se nanowires template.In this process,the amount of reducing agent is reduced.The linear structure of the NiSe₂ nanowires can provide rapid electron transfer and improve the hydrogen evolution performance.The related electrochemical performance tests show that the NiSe₂ nanowires after calcination have the best electrolyzed water performance.It has 196 mV the overpotential at the current density of 10 mA cm^-2,and 30.5 mV dec^-1 the tafel slope with good stability.3.A layer of amorphous Se was deposited on the etched titanium plate by chemical deposition.The Ti/NiSe₂ nanowire catalyst was successfully prepared by a similar method to the above.Studies have shown that the NiSe₂ catalyst prepared on the etched titanium plate has more hydrogen evolution performance and better stability.It has 208 mV the overpotential at the current density of 10 mA cm^-2,and 42.7 mV dec^-1 the tafel slope with good stability.