High entropy alloy nitrides with integrated nanowire/nanosheet architecture for efficient alkaline hydrogen evolution reactions

Abstract

High entropy materials (HEMs) are promising candidates as efficient hydrogen evolution reaction (HER) electrocatalysts, however, the facile fabrication of nanostructured HEMs over conventional catalyst supports remains a huge challenge. Herein, we report the in situ synthesis of FeCoNiCuMnN high entropy alloy nitrides (HEANs) with unique integrated nanowire/nanosheet architecture on carbon cloth (FeCoNiCuMnN/CC-400) by hydrothermal reaction and subsequent calcination at 400 °C under Ar/NH₃ conditions. The FeCoNiCuMnN nanosheets and nanowires connected with each other and were uniformly grown on the CC. A series of characterization studies have confirmed the formation of the FeCoNiCuMnN phases with uniform element distributions. FeCoNiCuMnN/CC-400 can be directly used as the electrocatalyst for alkaline HERs, and as a result, the FeCoNiCuMnN/CC-400 obtained an overpotential of 184 mV to achieve 10 mA cm⁻² and a small Tafel slope of 113 mV dec⁻¹. The long-term durability studies indicated that the current density was maintained at 23 mA cm⁻² in an alkaline electrolyte under continuous HER operations for 50 h, suggesting excellent corrosion and oxidation resistance.