Ultrathin Ru–Ni nanounits as hydrogen oxidation catalysts with an alkaline electrolyte

Abstract

The development of hydrogen–oxygen fuel cells with an alkaline electrolyte was highly limited by the sluggish kinetics of the hydrogen oxidation reaction (HOR). Here, with a pyrolysis-reduction route, a new RuNi-based electrocatalyst was prepared, which presents an ultrathin nanowire-like structure. In alkaline media, this catalyst shows an excellent catalytic performance with an exchange current density of 1.10 mA cm⁻²_disk for hydrogen oxidation. The exchange current density and mass activity of this catalyst are much higher than those of its single-metal counterparts and even the commercial Pt/C catalyst containing 20% Pt. Such a remarkable catalytic activity can be explained by the interaction between Ru and Ni; the incorporation of Ni may induce an electronic effect on the optimization of the Ru–H_ad strength and provide a functional surface that can absorb OH species, thus boosting the catalytic activity. These findings may cast a new light on the exploration of low-cost but high-efficiency catalysts for fuel cells.