The RuO2/NiRu heterogeneous interface optimizes the d-band center of the Ni–Ru catalyst for high-performance alkaline hydrogen evolution reaction

Abstract

Controlling the binding energy of hydrogen by introducing a secondary metal is an effective approach to design Ru-based electrocatalysts for improving the hydrogen evolution reaction (HER) performance. Here, we construct a series of multi-active site NiRu bimetallic materials with improved HER catalytic performance through a facile microwave synthesis method. Upon varying the Ni/Ru feeding ratio, the prepared Ni1Ru1/C sample was found to have the RuO₂/NiRu heterogeneous interface and showed the best HER performance. Only a 13 mV overpotential was observed at 10 mA cm⁻² in 1.0 M KOH solution, which is comparable to that of commercial Pt/C. Remarkably, lower overpotentials were achieved for the Ni1Ru1/C sample under industrially relevant current density conditions (higher than 500 mA cm⁻²) than commercial Pt/C. The HER activity for the Ni1Ru1/C sample can also be sustained at 400 mA cm⁻² for over 80 h with negligible degradation. The characterization and electrochemical experiment results illustrate that the excellent HER catalytic performance might be attributable to the enhancement of electrochemically active surface areas and the formation of the RuO₂/NiRu heterogeneous interface. DFT calculations further reveal a downshifted d-band center due to the presence of the RuO₂/NiRu heterogeneous interface, which appropriately weakens the too-strong adsorption of H* and thus improves the HER performance.