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

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 Mo 2 C 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. • Developed NiMoC electrocatalysts via a room-temperature, one-step magnetron co-sputtering technique. • Achieved a 62.8 % improvement in overpotential at 10 mA cm −2 by incorporating a separate carbon source. • Identified Mo₂C, NiMo, disordered carbon, and graphite-like carbon through material characterisation tests. • Achieved 26 mV and 42 mV overpotentials at 10 mA cm −2 with 10-day and 70-h stability in alkaline and acidic conditions, respectively. • Achieved remarkable performance in zero-gap electrolysers, with cell voltages of 1.78 V at 0.5 A cm −2 and 1.87 V at 1 A cm −2 , sustaining stability for 68 h.