Epitaxial growth triggered core-shell Pd@RuP nanorods for high-efficiency electrocatalytic hydrogen evolution

Ru with Pt-like hydrogen bond strength, knockdown cost (∼1/3 of Pt), and eximious stability is a competitive replacement for Pt-based catalysts towards the hydrogen evolution reaction (HER) in water splitting. The design of Ru-based catalysts via interface construction, crystal phase control, and specific light element doping to realize the impressive promotion of limited activity and stability remains challenging. Herein, we report the fabrication of Pd@RuP core-shell nanorods (NRs) via an epitaxial growth method, where ultrathin RuP shells extend the face-centered cubic (fcc) crystal structure and (111) plane of the Pd NRs core. Density functional theory results confirm that the core-shell interface engineering and P doping synergistically accelerate electron transfer and moderate the d-band center to generate a suitable affinity for H*, thus optimizing HER kinetics. Compared with Pd@Ru NRs and Pt/C, the Pd@RuP NRs exhibit preferable electrocatalytic stability and superior activity with a low overpotential of 18 mV at 10 mA cm−2 in the alkaline HER process. Furthermore, the integrated Pd@RuP//RuO2-based electrolyzer also displays a low operation potential of 1.42 V to acquire 10 mA cm−2, demonstrating great potential for practical water electrolysis. Our work presents an efficient avenue to design Ru-based electrocatalysts via epitaxial growth for extraordinary HER performance.