Advanced NiMoC electrocatalysts precision synthesised at room temperature for efficient hydrogen evolution across pH ranges

Abstract

Transition metal-based multi-metallic carbides are promising electrocatalysts for hydrogen evolution due to their catalytic properties. Synthesis is challenging due to agglomeration, scalability limits at high temperatures, and impurities. This study introduces a room-temperature, one-step magnetron co-sputtering technique to fabricate NiMoC electrocatalysts, achieving uniform carbon deposition with Ni and Mo. Integrating a carbon magnetron source with transition metals forms unique bonds, with controlled composition and thickness, enhancing catalytic performance. NiMoC demonstrates outstanding performance in alkaline conditions, with overpotentials of 26 mV at 10 mA cm⁻² and stability over 10 days. This represents that introducing a separate carbon source during magnetron co-sputtering improves NiMoC overpotential by 62.8 % at 10 mA cm⁻² compared to NiMo. These enhancements stem from Mo₂C and NiMo active sites, and improved conductivity and stability from disordered and graphite-like carbon. Sputtered NiMoC exhibits remarkable performance across pH levels, with 42 mV overpotential at 10 mA cm⁻² and stability over 70 h in acidic conditions. When integrated into a zero-gap electrolyser, NiMoC achieves excellent cell voltages of 1.78 V at 0.5 A cm⁻² and 1.87 V at 1 A cm⁻², maintaining stability for 68 h. These findings highlight magnetron co-sputtering's potential for room-temperature synthesis of multi-metallic carbides, advancing energy conversion.