Abstract

Catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are at the heart of water oxidation reactions. Despite continuous efforts, the development of OER/HER electrocatalysts with high activity at low cost remains a big challenge. Herein, a composite material consisting of TC@WO3@g-C3N4@Ni-NiO complex matrix as a bifunctional electrocatalyst for the OER and HER is described. Though the catalyst has modest activity for HER, it exhibits high OER activity thereby making it a better nonprecious electrocatalyst for both OER and HER and is further improved by g-C3N4. The catalytic activity arises from the synergetic effects between WO3, Ni-NiO, and g-C3N4. A Ni-NiO alloy and WO3 nanoparticles decorated on the g-C3N4 surface supported toray carbon (TC) matrix (TC@WO3@g-C3N4@Ni-NiO) by a facile route that show an excellent and durable bifunctional catalytic activity for OER and HER in the alkaline medium are developed. This carbon nitride with binary metal/metal-oxide matrix supported with TC exhibit an overpotential of 0.385 and 0.535 V versus RHE at a current density of 10 mA cm(-2) (Tafel slopes of 0.057 and 0.246 V dec(-1) for OER and HER, respectively), in 0.1 m NaOH. The catalyst is tested in water electrolysis for 17 h.