Preparation Of High Efficiency Electrolytic Water Catalyst By NiFe-LDH Percursors

The global energy crisis and its related environmental problems are growing.It is imperative to find renewable energy sources that can replace fossil fuels.Because of its high heating value,rich resources,and environmental friendliness,hydrogen energy is considered to be an attractive and promising energy source for future energy demand.Electrolyzed water is an efficient method of hydrogen production.Under energized conditions,extra energy can break H-O to form hydrogen and oxygen,and the by-products are oxygen,which plays an important role in industry,without any negative impact on the environment.At present,noble metal catalysts（Pt,IrO2）have the optimal catalytic performance,but their commercialization is limited by their high production cost and low reserves.Based on these,this article mainly studies the synthesis and electrochemical properties of NiFe-(CO₃^2-)-LDH and its phosphides.1.The NiFe-(CO₃^2-)-LDH nanosheet array was synthesized by using one-step hydrothermal method with nickel foam as the substrate.By controlling the concentration of Fe ions,the size of the nanosheets could be adjusted,thereby adjusting its electrochemical performance.The unique nanosheet structure can make the sample fully contact with the electrolyte to expose more catalytically active sites.At the same time,the foamed nickel substrate can accelerate the electron transfer rate.Electrochemical test results show that NiFe-(CO₃^2-)-LDH can be used as an OER catalyst and exhibits better catalytic activity than Ir O2.This study demonstrates the great potential of nickel-iron hydroxides for oxygen evolution in alkaline environments.2.The flower-like NiFe-(CO₃^2-)-LDH was synthesized based on a one-step hydrothermal method,and then a heterostructured Ni2P/Fe（PO3）2 was constructed by controlling the temperature of phosphating,and the nanostructure of Ni₂P/Fe（PO₃）₂ was regulated.The close contact between the catalyst and the nickel foam can improve the stability of the catalyst.Among them,the three-dimensional flower-like Ni2P/Fe（PO3）2exhibits excellent HER performance,OER performance,and full hydrolytic performance under alkaline conditions,and is superior to similar electrocatalysts.This research is of great significance in the direction of using nickel-iron phosphide for high-efficiency electrocatalysts.3.The flower-like NiFe-(CO₃^2-)-LDH synthesized by hydrothermal method was then annealed at low temperature to form Ni O/Fe2O3.The crystallinity and composition of the samples were changed by changing the annealing temperature,and the optimal electrocatalyst was selected.The three-dimensional nano-flower-like NiO/Fe₂O₃ has superior OER performance.This reasonable design should generally be suitable for significantly enhancing the catalysis of various transition metal-based compounds and many other applications.