Rh–Ni(OH)2/NF via hydrolysis galvanic replacement of boride: Unveiling an exceptional electrocatalyst for high-current alkaline hydrogen evolution

Abstract

The efficient and high-quality production for hydrogen through water electrolysis at high current densities is crucial for commercial utilization. However, the performance of existing hydrogen evolution reaction (HER) electrocatalysts is far from satisfactory. In this regard, we proposed a method to prepare Rh–Ni(OH)₂ catalyst based on Nickel foam (NF). The hydrolysis galvanic replacement of nickel boride with RhCl₃ led to produce a lattice contraction in Ni(OH)₂ due to the rigid pressure generated, resulting in outstanding HER performance at high current densities. It achieves an industrial current density of 500 mA cm⁻² with an overpotential of 130 mV. Furthermore, at the industrially prefer temperature of 80 °C, only 67 mV overpotential is required. The catalyst also demonstrated exceptional stability, maintaining excellent performance even after a stability test of 100 days with a current density of 200 mA cm⁻². Through Density-functional theory (DFT) calculations, Rh series reduced the hydrogen adsorption free energy.