Catalytic Activity toward Oxygen Evolution of LaFeO3 Prepared by the Microwave Assisted Citrate Method

LaFeO3 was prepared by the microwave-assisted citrate method and the catalytic activity for oxygen evolution reaction was investigated in HClO4 solution. The prepared sample was characterized by XRD, HRTEM and FESEM. XRD data showed that pure perovskite phase was indeed formed. The results suggested the successful incorporation of Fe3+ at the La3+ cations sites confirming the formation of the orthorhombic perovskite phase of LaFeO3. The particle size calculated from Scherrer equation was found to be 80.56 nm. The orthorhombic phase and the particle size were also ascertained by the HRTEM picture. FESEM image showed a porous and rough surface. Anodic linear polarization was used to evaluate the catalytic activity. The presence of the perovskite modifier increased the electrocatalytic activity toward oxygen evolution reaction (OER) by about 100 times, the current densities obtained at 1.5 V are 3.6 x 10(-5) and 1.2 x 10(-3) A/cm(2) for unmodified and modified surfaces, respectively. The order of reaction with respect to [H+] is close to unity and the calculated activation energy is 20 kJ/mol, which is much less than the values reported for several catalysts used for OER including some precious metal oxides. EIS results proved the high electrocatalytic activity of LaFeO3 toward OER. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.063209jes] All rights reserved.