Ultrafine CoRu alloy nanoparticles in situ embedded in Co4N porous nanosheets as high-efficient hydrogen evolution electrocatalysts.

Abstract

The development of hydrogen evolution reaction (HER) electrocatalysts with outstanding efficiency and favorable stability at all pH values is of great significance but still a dominating challenge toward the development of electrochemical water-splitting technology. Herein, CoRu alloy nanoparticles assembled in Co4N porous nanosheets (named as CoRu@Co4N) have been successfully achieved from Ru(OH)3@Co(OH)2 through a one-step nitridation process. Benefiting from the unique structure, inherent alloy properties and strong alloy-support interaction derived from the in situ transformation, the resultant hybrids exhibit superior HER activities over a wide pH range, achieving very low overpotentials of 13 mV, 44 mV and 15 mV at 10 mA cm-2 under alkaline, neutral and acidic conditions, respectively. Such activities surpass most reported electrocatalysts and are comparable or even transcendent to commercial Ru/C and Pt/C. Furthermore, CoRu@Co4N also exhibits outstanding stability during the accelerated degradation test (ADT) and chronopotentiometry. Our work provides a new approach for designing pH-universal Ru-involved HER electrocatalysts with remarkable efficiency and prominent durability.