Anomalous dominated (100) index facet endows ruthenium nanoparticles with accelerated alkaline hydrogen evolution

Ruthenium (Ru)-based materials are considered significantly promising alternatives to supersede platinum (Pt)-based catalysts toward the hydrogen evolution reaction (HER), especially under alkaline conditions. Herein, we adopt a gradual substitute method to rationally design phosphorus and nitrogen co-doped carbon matrix-supported Ru nanoparticles with an anomalous dominated (100) index facet (Ru(100)/NPC) for the efficient alkaline hydrogen evolution reaction (HER). Experimental and theoretical analyses confirmed that the water dissociation process is drastically boosted by the strong water adsorption at Ru sites with eight-fold coordination in Ru(100), while the efficient hydrogen generation process is achieved through hydrogen spillover to transfer hydrogen from the Ru sites with eight-fold coordination to Ru sites with ten-fold coordination in Ru(100) that demonstrated remarkable hydrogen formation activity. Consequently, the obtained Ru(100)/NPC exhibits an ultralow overpotential (16 mV) at 10 mA cm-2, much better than the commercial benchmark Pt/C. This work provides a new opportunity for the development of an ideal electrocatalyst for HER in alkaline media. We adopted a gradual substitute method to prepare (100) index facet-dominated ruthenium nanoparticles, on which water dissociation and hydrogen generation process was achieved at Ru sites with eight-fold and ten-fold coordination, respectively.