Strongly Coupled Architectures of Cobalt Phosphide Nanoparticles Assembled on Graphene as Bifunctional Electrocatalysts for Water Splitting

Efficient bifunctional electrocatalysts for both the cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) are crucial for water splitting in a sustainable energy system. A strategy for fabricating strongly coupled cobalt phosphide (CoP)/graphene (G) architectures composed of CoP nanoparticles and G is described. Benefiting from synergetic effects of a dual support system of CoP for electroactive sites and G to enhance charge transfer, low overpotentials of 120mV for the HER (0.5m H2SO4) and 292mV for the OER (1m KOH) are required to achieve current densities of 10mAcm-2. The as-prepared CoP/G composites, which serve as bifunctional catalysts for both HER and OER in complete water splitting, can generate a current density of 10mAcm-2 at 1.626V. The present strategy provides a novel and efficient method for configuring high-efficiency electrocatalysts for energy-related storage and conversion devices.