CuBP Microparticle Clusters (MPCs) as a Stable and Efficient Electrocatalyst for High-Current-Density Overall Water Splitting

Abstract

Developing stable and cost-effective electrocatalysts for electrochemical water splitting is essential for advancing sustainable hydrogen production. In this work, CuBP microparticle clusters (MPCs) electrocatalyst is demonstrated on a Ni foam substrate, fabricated by using a one-pot hydrothermal approach followed by post-annealing treatment. The optimized CuBP electrode exhibits impressive activities for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), showing overpotentials of 49 and 220 mV at 50 mA cm⁻² in 1 m KOH, which are comparable to benchmark Pt/C and RuO₂ electrodes. The bifunctional CuBP achieves a cell voltage of 1.52 V at 50 mA cm⁻², outperforming the Pt/C||RuO₂ systems and also demonstrating excellent stability over 120-h operations. At 2000 mA cm⁻², a voltage of 3.12 V is required in CuBP||CuBP configuration whereas the hybrid Pt/C||RuO₂ design exhibits a significantly lower cell voltage of 2.25 V at 2000 mA cm⁻². The superior catalytic behavior of the CuBP electrode can be attributed to the high active surface area due to the micro-particle topology, the optimal balance of Cu, B, and P, and the enhanced conductivity achieved through vacuum annealing. Overall, the CuBP electrode is highly efficient and has significant potential to replace traditional RuO₂ electrodes.