Preparation And Oxygen Evolution Performance Of Nickel-iron Hydrotalcite

In order to meet the challenges of energy crisis and environmental pollution,searching for renewable energy storage/conversion systems has attracted worldwide attentions.Among different methods,the electrolysis of water is an efficient way to produce hydrogen.It is well known that the oxygen evolution reaction?OER?is the half reaction of water splitting.However,the speed of OER is very slow with the transition of four electrons,hindering the overall efficiency of water decomposition.At present,RuO₂ and IrO₂ are considered to be the most efficient oxygen evolution electrocatalysts.Nevertheless,the scarcity and high cost of RuO₂ and IrO₂,make these materials are not suitable for the large-scale applications.In recent decades,transition metal oxide or hydroxide based electrode materials have been applied in this filed.Among these materials,the layered double hydroxide?LDH?materials,which have high OER activity,have attracted worldwide attention.In recent report,the catalytic activity of NiFe hydrotalcite materials can be equivalent to best precious metal catalyst.However,the limited specific surface area and low conductivity have impeded the practical application.In this work,the characteristics and defects of hydrotalcite materials have been discussed.The main research contents are as follows:?1?Bimetallic and trimetallic NiFeCo hydrotalcites were successfully obtained by one-step hydrothermal method.The trimetallic NiFeCo hydrotalcite with controlled Co incorporation is obtained,without further treatment.The addictive of Co,which will increase the surface area,the electronic conductivity and the number of active centers,enhances the catalytic activities of LDH.?2?NiFe-LDH/NF was prepared by the immersing of nickel foam in the aqueous solution containing Fe²⁺.The prepared method is simple,economical and environmentally friendly.The OER over-potential of the prepared material is only 265mV in 1 M KOH,demonstrating the high oxygen evolution performance.?3?NiFeAl ternary hydrotalcite was prepared by hydrothermal method.The amount of aluminum ions between the layers will have an obvious impact on the electrochemical properties of hydrotalcite,duo to the inert ion and low active site of aluminum.Therefore,the porous nickel-iron hydrotalcite catalyst,which was synthesized by an alkali etching process,depicts the enhanced catalytic activity.