Cu3P/NiO@NF heterostructure for highly efficient alkaline oxygen evolution reaction

Abstract

Electrochemical water splitting for the generation of hydrogen and oxygen is a promising approach for energy storage technologies. Exploring highly efficient and stable electrolytic water catalysts is the key to achieve economical and efficient hydrogen production. Heterostructured catalysts are composite materials distinguished by the presence of interfaces among their constituent components, which promote a synergistic effect that enhances their catalytic performance. In this study, we report a heterostructured catalyst, Cu₃P/NiO@NF, that is composed of Cu₃P/NiO on a three-dimensional nickel foam (NF) as an electrocatalyst for water splitting. This study focuses on the fabrication of heterojunctions and the application of phosphorization techniques for improving the catalytic efficiency of Cu₃P/NiO@NF for electrolytic water splitting. Cu₃P/NiO@NF was synthesized through a hydrothermal method and further optimized using high-temperature phosphorization to enhance its catalytic activity and long-term stability. Experimental results demonstrated that the Cu₃P/NiO@NF material exhibits superior electrocatalytic performance, with a current density of 10 mA cm⁻² at an overpotential of 86 mV, while maintaining excellent stability in alkaline solutions (with a Tafel slope of 41.07 mV dec⁻¹). These findings suggested that Cu₃P/NiO@NF heterostructures showed outstanding electrocatalytic performance for the oxygen evolution reaction in a 1 M KOH solution. The excellent electrocatalytic performance of Cu₃P/NiO@NF could be ascribed to its heterostructures, offering plentiful active sites and accelerating electrolyte penetration, thereby leading to synergetic effects. Additionally, O vacancies were formed on the surface by high-temperature phosphating, increasing catalytic surface activity and improving oxygen splitting performance.