Copper-doped cobalt oxide electrodes for oxygen evolution reaction prepared by magnetron sputtering

The Copper-doped cobalt oxide films have been prepared onto titanium support by reactive DC magnetron sputtering. The deposits are characterized by X-ray diffraction (XRD), energy-dispersive spectrometry (EDS), Ultroviolet (UV) and scanning electron microscope (SEM). The electrochemical characteristics of deposits are explored by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The effect of copper content in the Cu–Co oxides on the surface morphology, electrochemical and crystallographic properties has been investigated. The introduction of Cu element makes the Cu–Co oxides deposit fine and further lead to high roughness of deposits, which is helpful for the oxides’ electrochemical performance. Based on the electrochemical determination, the binary oxide electrodes exhibit better catalysis activity than that of CuO and Co3O4 electrodes for oxygen evolution reaction (OER). The increase OER activity has been attributed to the enlarged surface roughness and the new active sites of deposits, according to the results of EIS.

► The Cu–Co complex oxides were deposited by reactive DC magnetron sputtering.
► Doping of Cu makes the grain size reduced and favors the formation of the fine grain.
► Increasing Cu content enhances the catalytic activity of oxide electrodes.
► The Copper-rich Cu2CoO3 oxides show better performance for the OER.