Tailoring electronic environments of dispersed Ru sites for efficient alkaline hydrogen evolution

Abstract

Under the global initiative for carbon reduction, promoting alkaline hydrogen evolution reactions (HER) holds crucial significance. Ruthenium (Ru) demonstrates excellent hydrogen binding energy and offers a cost advantage over other platinum-group metals. However, the water dissociation capability of Ru sites in alkaline environments needs improvement, and the surface H* coverage is relatively low. In this work, a facile galvanostatic deposition strategy is employed to anchor Ru atoms onto a NiCo bimetallic oxide support (Ru–NiCoO₂/CC), enabling the modulation of the electronic environment of Ru sites. Benefiting from the optimized metal–support interactions, the prepared Ru–NiCoO₂/CC display excellent alkaline HER activity, requiring overpotentials of only 37 mV and 50 mV to achieve a current density of 10 mA cm⁻² in 1 M KOH and 1 M KOH + seawater, respectively. Meanwhile, it also has robust long-term stability. Importantly, the two-electrode electrolyzer with Ru–NiCoO₂/CC as the cathode requires only 1.71 V to achieve a current density of 50 mA cm⁻² for alkaline overall water splitting (OWS), and it also demonstrates potential for integration with intermittent energy systems. The synergy between hydrogen spillover and the phase transition induced by electrodeposited Ru improves the water dissociation capability and H* coverage on Ru sites. This work provides new insights for regulating Ru sites to achieve efficient alkaline hydrogen generation.