Non-equilibrium Plasma Activated Ultradurable Molybdenum Oxycarbide Electrocatalysts for Acidic Hydrogen Evolution up to 10 A cm-2

Electrocatalytic hydrogen evolution in acidic media at industrial-level current densities is limited by high overpotential, performance degradation, and thus low throughput. To address these issues, we developed a novel nanoedge-enriched molybdenum oxycarbide (MoO _x C _y ) electrocatalysts with a uniform phase by non-equilibrium plasma-enhanced chemical vapor deposition. The vertically standing MoO _x C _y exhibits low overpotential of 415 mV and outstanding long-term operational stability (~ 0.11% performance degradation over 1,000 h) at high current densities up to 10 A cm ^− 2 , corresponding to an ultrahigh hydrogen throughput of 4,477.4 L cm ^− 2 and a lifetime throughput of 407,033 L cm ^− 2 which exceed the department of energy (DOE) targets of 1,253.7 L cm ^− 2 and 100,503 L cm ^− 2 , respectively. Molybdenum oxycarbide catalysts outperform state-of-the-art transition metal- and even noble metal-based catalysts (throughput of 9 ~ 269 L cm ^− 2 and lifetime throughput of 8 ~ 269 L cm ^− 2 ) by more than an order of magnitude for throughput and three orders of magnitude for lifetime throughput. The key mechanisms enabling high catalytic performance and stability are achieved by incorporating carbon into MoO ₂ lattices, which reduces the valence state of Mo, leading to weakened binding energy of Mo-H and thus improved hydrogen evolution performance. Density functional theory results suggest that the presence of carbon atoms in MoO _x C _y increases the binding energy between Mo and the adjacent atoms, improving the stability of MoO _x C _y operating under harsh conditions. This work paves the way for the development of new transition metal-based catalysts for practical industrial electrocatalytic hydrogen evolution.