Electrocatalytic properties of La1-xCuxCoO3 (0 ≤ x ≤ 0.8) film electrodes for oxygen evolution in alkaline medium: Part II. A comparative study

Abstract

Abstract

The present study concerns with the preparation of perovskite-type oxide film electrodes of La, Cu and Co having composition La_1-xCu_xCoO₃ (0 ≤ X ≤ 0.8) on Ni conducting support by using low temperature sol-gel route at pH 4.00 and studied their electrocatalytic properties towards oxygen evolution reaction (OER) in alkaline medium.  X-ray diffraction study of the material indicated the formation of almost pure perovskite phase with hexagonal crystal geometry. The electrocatalytic activity of the material was determined in three electrode single compartment glass cell. Techniques used were cyclic voltammetry (CV), roughness factor and anodic polarization studies (Tafel plot). Each cyclic voltammogram exhibited an anodic and corresponding cathodic peak prior to the oxygen evolution reaction. The observed anodic and cathodic peak potential values were 553±31 and 312±27 mV, respectively. The study of anodic polarization curve indicates that the oxide with 0.6 mol Cu-substitution (j_a = 182.4 mA cm^-2 at 750 mV) showed highest electrocatalytic activity with lowest Tafel slope value (b = 65 mV decade^-1) towards OER. Thermodynamic properties of the material have also been investigated by recording the anodic polarization curve at different temperature. The value of electrochemical activation energy was found to be lowest with most active 0.6 Cu-substituted oxide material. Electrocatalytic activities of the oxide electrodes, so obtained, were compared with the similar oxide prepared at 3.75 pH.