NiWO3 Nanoparticles Grown on Graphitic Carbon Nitride (g-C3N4) Supported Toray Carbon as an Efficient Bifunctional Electrocatalyst for Oxygen and Hydrogen Evolution Reactions

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.