The Preparation And Electrochemical Performance Of Ni-Co-based Transition Metal Compounds As Hydrogen Evolution Catalysts

Energy and environmental issues are key issues of global concern,and the development of green and clean new energy sources is imminent.Hydrogen can be used to obtain thermal energy,and it can also be converted into electricity through electrochemical reactions.It is an ideal clean energy.Electrolyzed water has high hydrogen production efficiency and is the most promising and ideal method for industrial hydrogen production.On the negative electrode material,Pt/C catalyst has always occupied a major position.However,due to the high cost and lack of resources of precious metal catalysts,limiting its large-scale application,it is a hot research topic to find a high activity hydrogen evolution catalyst.In this paper,a series of transition metal phosphides were prepared by solvothermal method,and the electrocatalytic hydrogen evolution performance was studied in depth.The content is as follows:?1?We synthesized a 2D Ni P/Ni Co P/NG composite catalyst using a simplehydrothermal method and a calcination method.NG nanosheets provide a large surface area,which not only provides a good bridge for the integration of well-dispersed active materials,but also provides a composite structure with carbon-rich and nitrogen-rich active sites.Ni P/Ni Co P/NG shows excellent catalytic activity and stability in both acidic and alkaline media.To reach a current density of 10 m A cm^-2in 1M KOH and 0.5 M H₂SO₄solution,only over-potential 91 m V and 73 are required.m V.There are several reasons for its excellent catalytic activity and stability:the support of the 2D structure increases the specific surface area while providing more active sites,and the interface effect of the nano-heterojunction between Ni P and Ni Co P accelerates charge transfer,And additional synergy between Ni P/Ni Co P and NG.?2?We synthesized the Ni-Co-S/NG nanosphere composite nanosheet structure byhydrothermal in two steps.The effects of different curing temperatures on morphology and HER activity were studied.Ni-Co-S/NG-180?shows a lower overpotential of 169 m V to achieve a current density of 10 m A cm^-2,a Tafel slope of60 m V dec^-1 and a long-term stability up to 27 h.The reason why Ni-Co-S/NG-180?nanostructure has better HER activity than other catalysts is that the support of graphene provides a large number of exposed active sites,which accelerates the transport of electrons and ions;The heterostructure adjusts the electronic structure ofthe catalyst and reduces the free energy of H adsorption/desorption;the unique nano-spherical structure increases the surface area and provides more active sites for the reaction.Therefore,compared to 150°C and 200°C,Ni-Co-S/NG synthesized at180°C shows great catalytic performance in acidic solution.