Copper-Cobalt Oxides on FTO Substrate for Electrocatalytic and Pseudocapacitive Applications

In this work, we demonstrate an efficient layer-by-layer electrodeposition method to fabricate copper-cobalt oxide thin films on fluorine-doped tin oxide-coated (FTO) glass. Thermal treatment in the temperature range of 473-773 K was applied in order to obtain a stable oxide structure. The synthesized coatings were examined for their electrocatalytic application in both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) under alkaline conditions. These tests proved coating bifunctionality in water splitting half reactions along with their long-term stability. A multiple composition with a variety of oxo-species and oxidation states promotes coating application as pseudocapacitors by storing electric charge through the Faradaic reactions on the surface. During capacitance tests, copper-cobalt oxide films exhibited specific power as high as 1000 W kg(-1) at 1 A g(-1) current density.