Cobalt/molybdenum carbide@N-doped carbon as a bifunctional electrocatalyst for hydrogen and oxygen evolution reactions

Abstract

The development of cost-effective and highly active electrocatalysts for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) for overall water splitting is still a big challenge. Herein, we design and construct a composite architecture that is composed of nitrogen-doped carbon encapsulating cobalt and molybdenum carbide nanoparticles (Co_xMo_y@NC). Benefiting from synergistic cooperation between each component, the Co_xMo_y@NC presents excellent performance towards both HER and OER catalysis in alkaline medium. The optimized electrocatalyst is found to be Co₄Mo₂@NC, which only requires relatively low overpotentials of ∼0.218 V and ∼0.33 V to produce a current density of 10 mA cm⁻² for the electrocatalytic HER and OER, respectively. Such performance compares favorably to those of most previously reported Co, Mo-based electrocatalysts for water splitting. The present finding would enrich our knowledge to design and develop catalytically active molybdenum carbide-based electrocatalysts for overall water splitting.