Copper-based materials have attracted increasing attention for their earth-abundant and cheap characters for water splitting application. In the present work, a combined structure of Co3O4 nanoparticles and CuO microsheets was constructed in an aqueous system and studied as an efficient oxygen evolution reaction (OER) electrocatalyst. NH3 molecules as the ligand of metal ions (Cu2+ and Co2+) played vital roles for the uniform growth of Co3O4@CuO microsheets. The synergetic contribution of the two components made the composite samples behave excellent OER activity and fast kinetics both on glassy carbon electrode (GCE) and nickel foam (NF) substrates in alkaline medium. The remarkable small overpotentials (310 and 394 mV) can be obtained for CuO-Co-0.2/GCE sample at current densities of 1 and 10 mA/cm2 in 1.0 mol L−1 KOH (pH = 13.6). The in-situ deposited CuO-Co-0.2/NF achieved in the aqueous synthetic system demonstrates superior (structural and electrochemical) stability for 20 h-OER performance.
