Molecular Precursor Route to CuCo₂S₄ Nanosheets: A High-Performance Pre-Catalyst for Oxygen Evolution and Its...

Development of high-efficiency non-precious metal-based electrocatalysts to drive the complex four-electron process of the oxygen evolution reaction (OER) is crucial for production of hydrogen and energy storage components. Herein, bimetallic CuCo₂S₄ nanosheets were created by a new molecular precursor route. The optimal CuCo₂S₄ catalyst demonstrates superior performance to catalyze the OER with excellent stability, which was confirmed by the low overpotential of 290 mV at 10 mA cm^-2 in 1 M KOH. The catalytic activity can be maintained for at least 40 h. The catalyst after the OER was then detected. The results indicate that S-doped CoOOH/CuO nanosheets formed on the catalyst surface during the OER may act as the catalytic active substance. Furthermore, when employed as an air cathode in a Zn-air battery, it reveals a high open-cycle potential of 1.38 V and a peak power density of 123.9 mW cm^-2. The performance of the rechargeable Zn-air battery is close to that fabricated with commercial precious metal-based electrocatalysts. These findings would furnish some guidelines for the design, development, and applications of bimetallic sulfide electrocatalysts for the OER.