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

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 specialinterfacial structure is identified as one of the most efficient strategies to enhance the performance of waterelectrolysis 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 degrees C. Our work provides a promising avenue to regulate the interface superwetting property of Co-P electrodes and offers a facile and efficient strategy for designing high-efficiency catalysts with superaerophobic surfaces for practical water electrolysis.