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

The present study is concerned with the preparation of perovskite-type oxide film electrodes of La, Cu and Co having composition La1-xCuxCoO3 (0 <= x <= 0.8) on Ni conducting support and study of their electrocatalytic properties towards oxygen evolution reaction (OER) in alkaline medium. Materials have been synthesized by using malic acid sol-gel route at pH 4.00. 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 has been determined in three electrode single compartment glass cell. Techniques used in the electrochemical studies are cyclic voltammetry (CV), oxide roughness factor and anodic polarization (Tafel plot). Each cyclic voltammogram exhibits an anodic and a corresponding cathodic peak prior to the oxygen evolution reaction. The observed anodic and cathodic peak potential values are 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) shows 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 temperatures. The value of electrochemical activation energy has been found to be lowest with most active 0.6 mol Cu-substituted oxide material. Electrocatalytic activities of the oxide electrodes, so obtained, have been compared with the similar oxide prepared at 3.75 pH.