Cobalt manganese sulfide nanosheets: a robust bifunctional catalyst for alkaline water electrolysis

Abstract

Designing efficient and robust bifunctional electrocatalysts for overall water splitting (OWS) is crucial for advancing sustainable energy technologies. Nanosheet (NS)-like cobalt manganese sulfide (COMS) was synthesized in situ on nickel foam (NF) via a one-step hydrothermal method. The binder-free COMS NSs on NF electrocatalyst demonstrated low overpotentials of 197 mV and 270 mV for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), respectively, to achieve a current density of 10 mA cm⁻² in 1 M KOH. The electrocatalyst facilitated a low overall cell potential of 1.54 V to attain 10 mA cm⁻² current density, when utilized as both anode and cathode. COMS NSs on NF exhibited exceptional durability, ensuring stable operation over 300 h of continuous testing. The robustness of the electrocatalyst after long-term operation was examined with the aid of post-stability analysis. Additionally, density functional theory (DFT) was conducted to corroborate the experimental findings. All these outcomes emphasize that COMS NSs on NF are a highly promising earth-abundant electrocatalyst for alkaline water splitting.