Fabrication of covellite supported spinel oxide CuCo2O4 hybrid nano-composite electrode for efficient overall water splitting

Abstract

Hydrogen fuel being a green source of energy got attention as no harmful by-products are produced on its combustion. Hydrogen generation by water splitting via effective electrocatalyst is imperative. This study reports the synthesis of CuCo<inf>2</inf>O<inf>4</inf> supported on CuS via hydrothermal technique and use it as electrocatalyst for hydrogen generation. Electrocatalysis using CuS/CuCo<inf>2</inf>O<inf>4</inf> electrode in alkaline media, shows remarkably low overpotential of 286 and 135 mV at benchmark current density of 10 mA cm−2 for oxygen evolution and hydrogen evolution reactions (OER and HER), respectively. Strain and dislocation cause more defects in composite leading to increase in active sites. Modest Tafel value of 170 and 61 mV/dec for HER and OER, accordingly suggesting improved electrocatalytic efficiency and reaction kinetics of CuS/CuCo<inf>2</inf>O<inf>4</inf> nano-composite. The CuS/CuCo<inf>2</inf>O<inf>4</inf> nano-composite also shows higher values of TOF and electronic conductivity than CuS and CuCo<inf>2</inf>O<inf>4</inf>. Evaluation of durability over a 50-hour period shows little current loss, demonstrating that the generated nanocomposite's remarkable stability and it also shows high electrocatalytic active surface area (139.6 cm−2). © 2024 Elsevier B.V., All rights reserved.