Crafting MoC2-doped bimetallic alloy nanoparticles encapsulated within N-doped graphene as roust bifunctional electrocatalysts for overall water splitting

Despite recent vigorous progress in synthesis of monofunctional electrocatalysts for hydrogen evolution reaction (HER) or oxygen evolution reaction (OER), it remains challenging to develop bifunctional electrocatalysts for efficient overall water splitting. Herein, we report the crafting of MoC2-doped NiFe alloy nanoparticles (NPs) encapsulated within a-few-layer-thick N-doped graphene (denoted NG-NiFe@MoC2) via one-step calcination of hybrid precursors containing polymer-encapsulating binary Prussian blue analogues NPs and Mo6+ cations. The resulting NG-NiFe@MoC2 nanohybrids were exploited as electrocatalysts and exhibited excellent performance on either HER or OER separately as a direct consequence of the synergistic effects of unique compositions (i.e., MoC2 dopants and NiFe alloy NPs; both exerted profound influence on HER and OER) and advantageous architecture (i.e., a-few-layer-thick N-doped graphene encapsulating shell). Remarkably, an alkaline electrolyte capitalizing on NG-NiFe@ MoC2 nanohybrids as bifunctional electrocatalysts achieved overall water-splitting (i.e., concurrent HER and OER) current density of 10 mA cm(-2) at a low potential of 1.53 V over a period of 10-h operation, outperforming the precious Pt/C//RuO2 counterpart.