Phosphorus doping heterostructure La(OH)3@CuO @NF as an advanced electrocatalyst for the oxygen evolution reaction

Abstract

Due to the prevailing energy shortages, the pursuit of new alternative energy sources is becoming increasingly urgent. Hydrogen production through water electrolysis has emerged as a crucial method. However, the sluggish four-electron reaction in the oxygen evolution reaction (OER) remains the primary rate-limiting step. In this study, we synthesized a heterostructure La(OH)₃@CuO-P material on the nickel foam (NF) substrate. The experimental results demonstrate that after phosphating treatment, the heterostructure La(OH)₃@CuO-P exhibits exceptional catalytic performance with only 215 mV overpotential, a Tafel slope value of 79.36 mV/dec, and a bilayer capacitance of 39.02 mF/cm² at a current density of 10 mA/cm² for OER in a 1 M KOH solution. These values are significantly superior compared to those obtained using heterostructure La(OH)₃@CuO alone which showed an overpotential value of 365 mV at a current density of 10 mA/cm². Moreover, during cyclic voltammetry testing for up to 500 cycles, La(OH)₃@CuO-P also demonstrates relatively stable performance. Analyses suggest that composite heterostructure effectively addresses issues such as insufficient conductivity of La(OH)₃ and monomer aggregation tendency for CuO while maintaining excellent properties for each component. By incorporating P atoms as dopants, the interaction between La, Cu, and P atoms not only facilitates fine-tuning of the electronic structure and optimization of the adsorption free energy (-OH), but also promotes an increase in catalytic active sites through sample size reduction, thereby further augmenting the performance of the OER.