Co<sub>3</sub>O<sub>4</sub>/WO<sub>3</sub>/C Nanorods with Porous Structures as High-Performance Electrocatalysts for Water Splitting
Imtiaz Ahmed, Saptarshi Ghosh Dastider, Rathindranath Biswas, Ayan Roy, Krishnakanta Mondal, Krishna Kanta Haldar
Abstract
The recent promise of the hybridization of mesoporous carbon with transition metal oxides as a desirable catalyst for the oxygen evolution reaction (OER), and its extension to the hydrogen evolution reaction (HER) to achieve the goal of overall water splitting applications, remains a major challenge. Here, a unique environmentally benign mesoporous Co 3 O 4 /WO 3 /C bifunctional electrocatalyst is developed from converting cellulose waste, specifically in the form of sugarcane bagasse, by pyrolysis followed by a two-step hydrothermal strategy that can catalyze electrochemically OER and HER activity in an efficient and robust manner. The electrocatalyst delivers low overpotentials of 229/295 mV and a Tafel slope of 63/77 mV/dec –1 for both alkaline and acidic media, respectively, for OER along with the overpotential of 123 mV and a Tafal slope of 36 mV/dec –1 for HER to reach a current density of 10 mA/cm 2 . We hypothesized that an electronic synergistic effect between the transition metals might be responsible for promoting HER and OER activity, which was confirmed by density functional theory studies. This work opens a unique pathway to develop highly efficient, but low cost, electrocatalysts for water splitting applications.