Carbon-coated W-doped NiMoN catalysts with enhanced antioxidant properties for robust water electrolysis under fluctuating electricity

Abstract

For renewable energy-driven water electrolysis, developing low cost, highly active and durable electrocatalysts is essential. Here, we prepared a W-doped NiMoN microcolumn coated with a nitrogen doped carbon layer (W-NiMoN@NC) as an excellent non-precious electrocatalyst. This material displays excellent hydrogen evolution reaction (HER) activity with low overpotentials of 13 and 67 mV at 10 and 100 mA cm⁻², outperforming commercial Pt/C. DFT calculations show that W doping optimizes the water dissociation and H* adsorption processes, improving HER activity. Additionally, W doping coupled with an ultrathin NC coating enhances the intrinsic anti-oxidation ability of NiMoN. After 100 cycles of harsh fluctuating electrolysis, the incremental overpotential of W-NiMoN@NC is only 8 mV at 1000 mA cm⁻², significantly less than that of undoped NiMoN@NC (56 mV). The excellent anti-oxidation ability of W-NiMoN@NC resulting from its high reserves of Ni⁰ was proved by XPS analysis after fluctuating electrolysis. This inside-out strategy endows W-NiMoN@NC with an exceptional feature of long-term durability under harsh fluctuating conditions and a promising potential for application in renewable energy-powered electrolysis.