Electrodeposited cobalt phosphide film with regulated interfacial structure and wetting for enhanced hydrogen evolution performance: Effect of saccharin

Abstract

The exploration of earth-abundant and highly efficient catalysts for water electrolysis is vital for the sustainable development of future hydrogen economies but remains challenging. The rational construction of the special-interfacial structure is identified as one of the most efficient strategies to enhance the performance of water-electrolysis catalysts. Herein, cobalt phosphorus nanosheet arrays mediated by saccharin grown on copper foam (Co-P(SA)/CF) are rationally prepared via a facile one-step electrodeposition approach from a deep eutectic solvent (DES) consisting of choline chloride and ethylene glycol, known as Ethaline. Introducing SA increases the P content in the deposited Co-P composites with an optimized electronic structure and creates a superaerophobic surface to accelerate the hydrogen evolution reaction (HER). Such results significantly enhance the HER activity of Co-P(SA)/CF, requiring a small overpotential of 148.18 mV to drive 100 mA cm−2 in 1.0 M KOH. Impressively, Co-P(SA)/CF provides remarkable HER stability and can maintain 100 mA cm−2 over 165 h for continuous electrolysis operation in 6 M KOH at 80°C. Our work provides a promising avenue to regulate the interface super-wetting property of Co-P electrodes and offers a facile and efficient strategy for designing high-efficiency catalysts with superaerophobic surfaces for practical water electrolysis.