Tailoring the bifunctional electrocatalytic activity of nickel-cobalt sulfides derived from ZIF-67 by cerium doping to enhance the overall water splitting performance

Abstract

To stay current with energy development, designing efficient bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media is urgent. Herein, cerium is incorporated into ZIF-derived sulfides to create (Ce)NiCo–S/NF, a composite material with a nanogrid-like hierarchical structure. Importantly, it required a low overpotential of 136 mV at 10 mA cm⁻² for the HER. For the OER, it achieved current densities of 10 and 50 mA cm⁻² at low overpotentials of 209 and 245 mV, respectively. Creating a nanogrid-like hierarchical microstructure with a core-shell structure and modulation of the electronic environment through cerium doping is believed to be responsible for the improved electrocatalytic efficiency. In addition, overall water splitting demanded a low cell voltage of 1.57 V to achieve a current density of 10 mA cm⁻². This research outlines a feasible framework for an efficient material for global clean energy applications.