Nickel-Tungsten Nano-Alloying for High-Performance hydrogen Electro-Catalytic oxidation

Abstract

• Development of NiW nano–alloy as a novel HOR electro–catalyst. • The preparation process of NiW nano–alloy is facile, cost effective and scalable. • NiW nano–alloy shows much enhanced HOR catalytic activity and stability. • A possible reaction mechanism has been proposed. The efficient and low-cost electro-catalysts towards hydrogen oxidation reaction (HOR) are vitally important to the commercialization of fuel cells, which, however, have been rarely paid attentions. Herein, NiW nano-alloy electro-catalysts (∼3 nm) grown in-situ on carbon paper (NiW/CP) have been designed and synthesized by a facile and rapid (in 14 min) electro-deposition method. This alloying strategy greatly enhances the H 2 adsorption energy meanwhile reduces metal-hydrogen bonding strength on the catalyst surface, leading to the substantially lowered hydrogen oxidation energy barrier and consequently the remarkably elevated HOR catalytic activity in H 2 -saturated 0.1 M KOH electrolyte (3.26 mA cm −2 at 0.05 V vs. RHE), which is significantly higher than that of Pt/C electro-catalyst. Especially, NiW/CP shows extraordinarily high stability during 30,000 cycles and outstanding CO tolerance. Furthermore, both thermodynamic and kinetic first-principle calculations demonstrate that the HOR performance of Ni(1 1 1) can be largely enhanced by W alloying.