An interfacial electron transfer relay center for accelerating the hydrogen evolution reaction

Motivated by the interaction between different regions at the interface for promoting hydrogen evolution reaction (HER) kinetics, a one-dimensional Mo/Mo₂C@graphene (Mo/Mo₂C@G) heterointerface electrocatalyst consisting of Mo/Mo₂C as the core and thin graphene layers as the shell was designed via facile carbonization of the Mo-polymelamine hybrid precursor in this work. The interconnected interfaces formed between Mo and Mo₂C combined with the outer carbon capping layers endowed the as-obtained electrocatalyst with outstanding HER activity with a low overpotential of 145 mV at 10 mA cm^-2 and even lower than that of commercial Pt/C when the current density exceeded 46.5 mA cm^-2, as well as a small Tafel slope of 78 mV dec^-1. Moreover, great HER durability from the one-dimensional nanostructures was confirmed by the 30 h continuous test and 3000 cycle long-term operation under alkaline conditions with negligible current loss. Density functional theory calculations reveal the pivotal role of the highly electroactive interfacial region in enhancing the HER performance. The pinned carbon atoms constitute a key electron transfer relay center for facilitating the smooth HER performance. This unique nanointerface design enriches highly accessible active sites and holds promising potential for developing efficient and stable noble-metal free HER catalysts in basic media.