Schottky Junctions Formed by MoNi Alloys and Molybdenum Carbide Quantum Dots on Hollow Carbon Nanospheres as Hydrogen Evolution Electrocatalysts

Abstract

The development of stable, low-cost catalysts with low overpotentials for the hydrogen evolution reaction (HER) is a necessary step in replacing expensive Pt-based catalysts for future energy revolution. In this study, we propose an interfacial engineering strategy to prepare a non-noble-metal-based catalyst with a Schottky junction formed between molybdenum–nickel alloys and molybdenum carbide quantum dots on N-doped carbon nanospheres (MoNi/MoC_x/NCS). The strong interfacial interaction of the Schottky junction, combined with the interface coupling of the N-doped carbon support, adjusted the charge redistribution between Ni and Mo, optimized the d-band center, improved the charge/mass transfer dynamics, and significantly enhanced the hydrogen evolution performance of the MoNi/MoC_x/NCS catalyst. It exhibits overpotentials of 77 and 166 mV to achieve current densities of 10 and 100 mA cm^–2, respectively, with a small Tafel slope of 54.1 mV dec^–1. It shows superior cycling stability with no observable overpotential decay after 5000 cycles and exceptional stability at 40 mA cm^–2 for 100 h of continuous HER operation with negligible current attenuation. These results highlight the potential of the MoNi/MoC_x/NCS catalyst as a highly efficient and stable non-noble-metal-based catalyst for hydrogen evolution reaction applications.