RuIn Solid-Solution Alloy Nanoparticles with Enhanced Hydrogen Evolution Reaction Activity

We report the synthesis of novel RuIn solid-solution alloy nanoparticles (NPs) via the electrochemical cleaning of RuIn@InOx NPs. By alloying In to Ru, the RuIn NPs exhibited enhanced hydrogen evolution reaction (HER) activity compared with monometallic face-centered cubic (fcc) Ru NPs. Furthermore, the HER activity of RuIn NPs was comparable to that of commercial Pt catalysts. At a current density of 10 mA cm–2, RuIn NPs displayed a lower overpotential of 30.7 mV compared to monometallic fcc Ru NPs (57.8 mV) and commercial Pt NPs/C (34.1 mV). X-ray photoelectron spectroscopy and X-ray absorption near edge structure analysis revealed charge transfer from In to Ru in RuIn NPs. The results indicate that the alloying of In with Ru leads to beneficial intermetallic charge transfer, which efficiently modulates the desorption energy barrier to intermediate H* and enhances the intrinsic HER performance of monometallic fcc Ru NPs.