Ru anchored on Mo@MoO_x nanowires as self-supported electrocatalysts for efficient hydrogen production in alkaline media

Ru-based materials are expected to be a promising alternative to commercial Pt/C for electrocatalytic hydrogen evolution reaction (HER), but they still suffer from large overpotential and low mass activity in alkaline medium. Here, we reported Ru (∼0.24 wt%) anchored on the Mo@MoO_x nanowires (Ru−Mo@MoO_x) as an efficient alkaline HER electrocatalyst. The Ru−Mo@MoO_x nanowires exhibit a considerably low overpotential of only 16 mV at 10 mA cm⁻² and a Tafel slope of ∼30 mV dec⁻¹ in a 1 M KOH aqueous solution, which outperform those for commercial Pt/C and most reported Ru-based electrocatalysts. Electrochemical and structural investigations reveal that Mo@MoO_x support can modulate electronic structure of Ru active sites, leading to the optimizations of adsorption and dissociation for H₂O. Meanwhile the improved electron and mass transfer also contribute to the HER performance. The water electrolyzer using Ru−Mo@MoO_x as the cathode afford a stable voltage of ∼1.47 V to deliver 10 mA cm⁻².