Phosphorus-Tuned Co-P Alloy Coatings for High-Performance Water Splitting and Hydrogen Production

The production of green hydrogen through water splitting is considered to be one of the most environmentally friendly and practical solutions to address the global energy crisis and mitigate the greenhouse effect. A primary challenge in the field concerns the development of efficient, stable, and cost-effective electrocatalysts capable of facilitating both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), particularly in alkaline media. In this study, Co-P alloy coatings with different P contents were deposited on the copper (Cu) surface using a straightforward and sustainable electroless metal deposition technique. The morphology, structure, and composition of the Co-P coatings were analysed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Furthermore, the catalytic activity of the coatings for HER and OER in 1 M KOH was investigated using linear sweep voltammetry (LSV) and chrono-techniques. The Co-P coating with 11 wt% P exhibited the lowest overpotential of 98.9 mV for the HER to achieve a current density of 10 mA cm^-2, thereby demonstrating superior performance compared to the Co-P coatings with 8, 5, 1.6, and 0.4 wt% P. Conversely, the Co-P coating with 8 wt% P exhibited the lowest overpotential of 378 mV for the OER to achieve the same current density of 10 mA cm^-2, in contrast to the coatings with 5, 11, 1.6 and 0.4 wt% P. These high-performance, P-tuned Co–P coatings demonstrate considerable potential for sustainable hydrogen production and scalable renewable energy storage applications.

Acknowledgement

This research was funded by a grant (No. P-MIP-23-467) from the Research Council of Lithuania.