Preparation And Water Electrolysis Performance Of Molybdenum Nickel Oxide Electrocatalyst

Fossil fuels occupy a dominant position in the current energy structure,and oil,natural gas and other energy sources have fully penetrated into people’s production and life,promoting economic development but also causing serious pollution.The greenhouse effect is becoming more and more obvious,and water and air pollution are becoming more and more serious,affecting people’s life.In this context,the combustion process of hydrogen,which produces only heat and water,has received a lot of attention.Water electrolysis technology is the most promising industrial and sustainable hydrogen production method among many hydrogen production technologies.However,the current widely used water electrolysis technology has low efficiency and high energy consumption,so it is necessary to further improve the energy conversion efficiency and reduce the cost.Therefore,the key to solve the problem of electrolytic water technology is to develop a catalyst with lower energy consumption and higher efficiency.This paper mainly studies the preparation of molybdenum-nickel oxide electrocatalyst,morphology regulation and electrochemical performance analysis,the application of hydrothermal method,hydrogen reduction method and other chemical methods,by changing the carrier,reduction temperature and other ways to synthesize Ni-MoO₂@SCG nanoparticles and Ni₂Mo₃O₈NWS@NF nanowire materials with unique core-shell structure.Furthermore,the morphology and structure of the prepared material were characterized,and the electrochemical performance of the material was tested and analyzed,so as to understand the electrochemical performance characteristics of the material and the catalytic principle.The research contents of this paper are as follows:（1）Preparation and catalytic performance of Ni foam-supported Ni₂Mo₃O₈nanowires electrocatalystsNiMoO₄·x H₂O nanowire was generated on the surface of nickel foam by one-step hydrothermal method,and molybdonickel oxide nanowire with different composition was obtained by controlling the reduction temperature.Among them,Ni₂Mo₃O nanowire has the largest electrochemical active area,the smallest impedance,the largest number of micropores and the unique synergistic effect of MoNiO atoms,which makes the electron energy level of Mo⁴⁺redshift and improves the binding energy of catalyst and H,resulting in its best electrocatalytic hydrogen evolution reaction activity.The performance is optimal at both low and high current densities(η₁₀=17.6 mV,η₁₀₀=95 mV).At the same time,it shows good stability at low current density.After 100 hours of stability test,the overpotential is reduced by only 6.3 mV,which has good stability.（2）Preparation and catalytic performance of Ni-MoO₂core-shell nanoparticles supported by three-dimensional grapheneDue to the characteristics of large specific surface area,high conductivity and porosity of three-dimensional structure graphene,the Ni-MoO₂precursor NiMoO4·x H₂O was anchored on the micropores after hydrothermal process and high temperature hydrogen reduction.After reduction,Due to the low solubility of Ni in the metal oxide MoO₂,Ni was extracted from the double oxide to form a core-shell structure.The average size is about 20 nm.Due to the fact that Ni-MoO₂@SCG is based on stereo-structured graphene,has a specific surface area of 156.65 m²g^-1,and abundant micropores and mesopores within 20 nm,it shows the highest electrochemical active area,and a strong electron transfer phenomenon occurs at the core-shell interface,which increases the electrolytic water reactivity of the catalyst.The current density of 10 m A cm^-2can be achieved with an overpotential of 80 mV and 278 mV,respectively,in hydrogen evolution and oxygen evolution tests.A current density of 10 m A cm^-2is achieved at a voltage of 1.548 V in the fully dissolved water test.After 20 h stability test,the overpotential basically unchanged,has a good stability.