Engineering Ternary Copper-Cobalt Sulfide Nanosheets as High-performance Electrocatalysts toward Oxygen eVolution Reaction

The rational design and development of the low-cost and effective electrocatalysts toward oxygen eVolution reaction (OER) are essential in the storage and conversion of clean and renewable energy sources. Herein, a ternary copper-cobalt sulfide nanosheets electrocatalysts (denoted as CuCoS/CC) for electrochemical water oxidation has been synthesized on carbon cloth (CC) via the sulfuration of CuCo-based precursors. The obtained CuCoS/CC reveals excellent electrocatalytic performance toward OER in 1.0 M KOH. It exhibits a particularly low overpotential of 276 mV at current density of 10 mA cm⁻², and a small Tafel slope (58 mV decade⁻¹), which is superior to the current commercialized noble-metal electrocatalysts, such as IrO₂. Benefiting from the synergistic effect of Cu and Co atoms and sulfidation, electrons transport and ions diffusion are significantly enhanced with the increase of active sites, thus the kinetic process of OER reaction is boosted. Our studies will serve as guidelines in the innovative design of non-noble metal electrocatalysts and their application in electrochemical water splitting.