Boosting alkaline hydrogen evolution performance of Co4N porous nanowires by interface engineering of CeO2 tuning

Abstract

Developing high-efficiency non-precious electrocatalysts for alkaline hydrogen evolution reaction (HER) is critical for practical application in water splitting. Abundant HER electrocatalysts exhibit high activity in acids, but deliver inferior performance in alkalis due to sluggish kinetics. Herein, motivated by the promoter CeO₂ (rich in oxygen vacancies) that can modulate the electronic structure of materials, a high-efficiency catalyst of Co₄N nanowires by coupling CeO₂ vertically grown on Ni foam (Co₄N–CeO₂/NF) is prepared by composition control and interface engineering. Anchoring CeO₂ into Co₄N will endow the catalyst with superhydrophilic and superaerophobic properties, and simultaneously promote water adsorption/dissociation, which dramatically boost the alkaline HER performance. The as-synthesized self-supported Co₄N–CeO₂/NF electrode exhibits fairly low overpotentials of 52 and 149 mV at current densities of 10 and 100 mA cm⁻² for HER in 1.0 M KOH electrolyte, respectively. Furthermore, after a long-time operation of 24 h at a fixed high current density of 100 mA cm⁻², the required overpotential is increased only by 4 mV, showing the extraordinary long-time durability and promising potential in mass applications. This work will provide an effective strategy for rational design and activity enhancement of other non-precious metal-based HER electrocatalysts.