Synergistic effect of ultrafine nano-Ru decorated cobalt carbonate hydroxides nanowires for accelerated alkaline hydrogen evolution reaction

Rational design of combined noble metals and earth abundant metal-based materials is important in the development of highly active and stable electrocatalysts with reduced noble metal loading toward hydrogen evolution reaction (HER). As a cheaper alternative to platinum (Pt), ruthenium (Ru) has similar bond strength with hydrogen. In this work, we develop carbon fiber-supported cobalt carbonate hydroxides nanowires for the deposition of Ru (CF@Ru–CoCH NWs) and achieve high HER performance under alkaline condition. Such novel catalyst exhibits a low Tafel slope (65 mV dec −1 ), small overpotential of, respectively, 66 and 121 mV at geometrical current density of −10 and −100 mA cm −2 . The superior performance, comparable to commercial Pt for HER, is attributed to the synergistic effect from Ru nanoparticles (NPs) and cobalt carbonate hydroxides nanowires (CoCH NWs). Dual-pathway kinetic analysis confirms that the CoCH NWs are able to lower the energy barrier of the Volmer step while Ru improves the Heyrovsky step to form hydrogen gas, thereby enhancing overall HER activity.