The cathodic hydrogen evolution reaction (HER) in alkaline media suffers from intrinsically slow kinetics due to the high energy barrier of the obligatory water-dissociation step, which induces substantial overpotentials and limits overall energy conversion efficiency. Consequently, the precise engineering of high-performance electrocatalysts remains indispensable for advancing sustainable energy conversion technologies. Herein, we report the rational design of Ru-enriched Ni/C catalysts featuring highly dispersed Ru sites synthesized via a low-temperature route to induce controlled surface enrichment and strong metal–support interactions. Among the synthesized series (5, 10, and 15 wt % Ru), the optimized 10 Ru–Ni/C catalyst exhibits outstanding catalytic activity, requiring an overpotential of only 28 mV to reach 10 mA/cm 2, thereby surpassing commercial Pt/C (30 mV @ 10 mA/cm 2 ) under identical conditions. Comprehensive electrochemical analysis reveals a low Tafel slope of 36 mV dec –1, confirming accelerated HER kinetics following a Volmer–Tafel pathway, along with excellent operational durability over 500 h across a wide current density range. X-ray and microscopic characterizations confirm the successful formation of highly dispersed Ru species and lattice-modified Ni frameworks that prevent surface aggregation. Furthermore, density functional theory calculations demonstrate that Ru incorporation modulates the local electronic d-band center of Ni, optimizing hydrogen adsorption free energy toward thermoneutral values. This work highlights an effective strategy for tuning nonprecious metal catalysts with minimal noble metal loading, offering insights into the design of high-performance electrocatalysts for sustainable hydrogen production.
Iqbal et al. (Thu,) studied this question.