Metastable face-centered cubic ruthenium-based binary alloy for efficient alkaline hydrogen oxidation electrocatalysis

Metastable nanostructured electrocatalyst with a completely different surface environment compared to conventional phase-based electrocatalyst often shows distinctive catalytic property. Although Ru-based electrocatalysts have been widely investigated toward hydrogen oxidation reaction (HOR) under alkaline electrolytes, these studies are mostly limited to conventional hexagonal-close-packed ( hcp ) phase, mainly arising from the lack of sufficient synthesis strategies. In this study, we report the precise synthesis of metastable binary RuW alloy with face-centered-cubic ( fcc ) phase. We find that the introduction of W can serve as fcc phase seeds and reduce the formation energy of metastable fcc -RuW alloy. Impressively, fcc -RuW exhibits remarkable alkaline HOR performance and stability with the activity of 0.67 mA cm Ru −2 , which is almost five and three times higher than that of hcp -Ru and commercial Pt/C, respectively, which is attributed to the optimized binding strength of adsorbed hydroxide intermediate derived from tailored electronic structure through W doping and phase engineering. Moreover, this strategy can also be applied to synthesize other metastable fcc -RuCr and fcc -RuMo alloys with enhanced HOR performances.