A Nanostructured Ru-Mn-Nb Alloy with Oxygen-Enriched Boundaries for Ampere-Level Hydrogen Evolution

Development of active and cost-effective electrocatalysts to substitute platinum-based catalysts in alkaline hydrogen evolution reactions (HERs) remains a challenge. The synergistic effect between different elements in alloy catalysts can regulate electronic structure and thereby provide an abundance of catalytic sites for reactions. Thus, alloy catalysts are suitable candidates for future energy applications. Conventional methods for enhancing the performance of alloy catalysts have mainly focused on element composition and thus have often neglected to examine catalyst design. In this paper, a ruthenium-manganese-niobium alloy catalyst (Ru₆₂Mn12Nb₂₁O₅) is reported with a supra-nanocrystalline dual-phase structure that is fabricated through combinatorial magnetron co-sputtering at ambient temperatures. The induced crystal-crystal heterostructure of Ru₆₂Mn₁₂Nb₂₁O₅ reduced system energy, thereby achieving balance between stability and catalytic activity. Ru₆₂Mn₁₂Nb₂₁O₅ exhibited excellent HER performance, as demonstrated by low HER overpotential (18 mV at 10 mA cm^-2) and robust stability (300 h at 1.2 A cm^-2). Moreover, oxygen-rich interfaces in Ru₆₂Mn₁₂Nb₂₁O₅ enhanced charge transfer and the kinetics of water dissociation as well as optimized hydrogen adsorption/desorption processes, thus boosting HER performance. The crystal-crystal heterostructure and oxygen-rich interfaces in Ru₆₂Mn₁₂Nb₂₁O₅ are induced by its dual-phase nanocrystalline structure, which represents a new structural design for enhancing the performance of catalysts for sustainable energy development.