Preparation Of Self-supporting Cobalt-based Nanoarray Bifunctional Catalysts And Performance For Water Electrolysis

Hydrogen with excellent energy conversion efficiency,high gravimetric energy density than gasoline(120 vs.44 MJ kg-1),zero carbon dioxide emission,and environment compatibility has been widely recognized as the most ideal alternative to the fossil fuels.Water electrolysis has been regarded as a pollution-free and promising approach for generating hydrogen operating under mild conditions and powered by renewable energy.Transition-metal based materials have attracted tremendous attention to replacing the noble-metal HER and OER catalysts due to their unique surface electron structure.Nanoarray catalysts have high specific surface area and more exposed active sites.Therefore,it is of great significance for the development of renewable energy to prepare efficient and low-cost bifunctional nanoarray electrocatalytst for overall water splitting.Based on this,P-doped RuCo nanowires array catalysts and CoNiP/NF nanoarray catalysts have been prepared in this paper.The main contents are as follow:Firstly,RuCoP/NF nanowires array catalysts were prepared on nickel foam(NF)substrate by hydrothermal and low-temperature phosphating.RuCoP/NF demonstrates superior performance for HER(44 mV@10 mA cm-2)and OER(379 mV@50 mA cm-2)in 1.0 M KOH electrolyte solution.The overall water splitting system was assembled by using RuCoP/NF as both anode and cathode.Besides,it exhibits a voltage of 1.533 V at the current density of 10 mA cm-2 and long-term durability within 24 h.Through a series of characterization,this study proved that the excellent catalytic performance of RuCoP/NF is mainly attributed to the doping of P and the unique nanowires structure,which is conductive to the improvement of overall water splitting reaction kinetics.This study offers novel understanding for highly effective bifunctional nanoarray materials by phosphorus-doped and the introduction of trace amount of noble-metal.Secondly,3D CoNiP/NF nanoarrays catalysts were prepared on nickel foam(NF)substrate by hydrothermal and low-temperature phosphating.In this paper,CoNi-based bifunctional overall water splitting electrocatalysts with different morphologies and structures were prepared by adjusting the addition of Co salt and Ni salt.CoNiP/NF demonstrates superior performance for HER(162 mV@10 mA cm-2)and OER(499 mV@100 mA cm-2)in 1.0 M KOH electrolyte solution.The overall water splitting system was assembled by using CoNiP/NF as both anode and cathode.Besides,it exhibits a voltage of 1.613 V at the current density of 10 mA cm-2 and long-term durability within 24 h.This work provides a new understanding for the preparation of ternary non-noble metal based bifunctional water electrolysis catalyst with different morphologies.