The Study Of Preparation Of Nickel-based Bimetallic Catalysts And Their Electrolyzing Water Performance

With the rapid development of social economy and technological progress,people’s demand for energy is increasing day by day.The energy crisis and environmental pollution have become two urgent problems that need to be resolved.Hydrogen is considered to be a clean and ideal renewable fuel in the future.Its oxidation product is water and does not contain pollutants.In addition,the combustion enthalpy of hydrogen fuel is higher than any other chemical fuel.Water electrolysis is considered to be an ideal hydrogen production method,and it has been a research hotspot in recent years.Theoretically,electrochemical water splitting only requires a voltage of 1.23 V.However,it is necessary to overcome the activation barrier of the electrolysis reaction by a relatively high voltage（usually>1.8 V）in practice.Generally,noble metal-based electrocatalysts（such as Pt,Ir,Ru,etc.）are recognized as the best HER and OER catalysts,but noble metal catalysts are scarce and expensive in nature,which limits their large-scale applications.At present,transition metal materials represented by Ni and Mo have attracted wide attention of researchers due to their abundant chemical state and low cost.This paper designs and synthesizes different kinds of Ni-Mo-based bimetallic catalysts to satisfy HER,OER and overall water splitting.First,the Ni Mo precursor grown on carbon cloth was synthesized by hydrothermal method,and then reduced to Mo Ni₄-Mo O₂/CC porous structure by high-temperature calcination in a reducing atmosphere.At the same time,Ni-Mo O₂/CC,Mo Ni₄-Mo₂C/CC were prepared at different temperatures.The electrochemical test results show that the Mo Ni₄ nano-alloy has high intrinsic activity,and the unique porous structure can exposes more active sites,which ultimately promotes the Mo Ni4-Mo O₂/CC catalyst to obtain a current density of only 1.49 V at 10 m A cm^-2 lower voltage,with an excellent catalytic performance for overall water splitting.The Ni Mo precursor was phosphatized at high-temperature in a reducing atmosphere by chemical vapor deposition,and the Ni Mo P₂-Ni₂P/CC heterostructure was successfully prepared.The Ni Mo P₂-Ni₂P heterostructures grown on carbon cloth as a freestanding integrated electrode exhibited excellent oxygen evolution reaction（OER）activity and hydrogen evolution reaction（HER）activities with low overpotentials(258 m V and 53 m V to reach 10 m A cm^-2 for the OER and HER,respectively),and small Tafel slope(45 m V dec^-1 and 58 m V dec^-1 for the OER and HER,respectively).Moreover,the Ni Mo P₂-Ni₂P heterostructure can act as both anode and cathode catalysts for overall water splitting with low overall potential of 1.48 V at10 m A cm^-2.Density functional theory（DFT）suggests that the amorphous heterogeneous interfaces play an essential role in enhanced catalytic performance.