Effect of Cu-doping on the activity of calcium cobaltite for oxygen evolution reaction

[Display omitted] •Preparation of Cu-doped calcium cobaltite by proteic sol–gel method.•Cu doping decreases the surface area available for OER.•Mechanical and chemical stability is not affected by Cu doping. Herein, the effect of Cu-doping on the OER activity of misfit calcium cobaltites (Ca3Co4-xCuxO9+δ; x = 0, 0.05, 0.10, and 0.15) was evaluated under an alkaline medium. Powders obtained by a proteic sol–gel method were systematically studied using a variety of characterization techniques. Rietveld refinement from XRD data revealed that there was no change in the crystalline structure of the doped cobaltites. Electrochemical analyses showed that the performance of the catalysts decreases with increasing the amount of Cu. Electrochemical impedance spectroscopy revealed that the polarization resistance (RP) increases with the degree of doping, harming the kinetics of faradaic processes in OER.