Highly efficient oxygen evolution electrocatalysts based on nanosheet-shaped CuS in situ grown on carbon cloth

In this work, nanosheet-shaped CuS (NSCuS) is successfully grown on carbon cloth (CC) by a two-step route in combination with electrodeposition and hydrothermal treatment via in situ sulfidations of Cu2O and Cu with exposure to thiourea at 120 °C or 24 h. Transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffractometry are performed to characterize the microstructure, morphology, composition, and crystal structure of the NSCuSCC samples. The electrochemical measurements demonstrate that the synthesized NSCuSCC electrocatalysts possess outstanding oxygen evolution reaction (OER) performance and superior long-term durability in 1 M KOH electrolyte. In particular, the NSCuSCC synthesized via the electrodeposition process at an applied current of 1.5 mA shows a low overpotential for the OER (358 mV at 10 mA/cm2), which is close to that of commercial IrO2 (346 mV at 10 mA/cm2). The exceptional OER property is ascribed to the NSCuS having a large surface area to offer abundant reaction active sites and to the CC network structures supplying more ions and charge transfer channels during the electrocatalytic process.