Synthesis and Characterization of La(0.6)Ca(0.4)Co(0.8)Ru(0.2)O(3) for Oxygen Reduction Reaction in an Alkaline Electrolyte

Abstract

We employed an amorphous citrate precursor (ACP) method to synthesize stoichiometric La(0.6)Ca(0.4)Co(0.8)Ru(0.2)O(3) powders. Result from X-ray diffraction demonstrated a perovskite La(0.6)Ca(0.4)CoO(3) lattice, indicating the incorporation of Ru(3+) at the Co(3+) sites. Image from the scanning electron microscope revealed a foamlike microstructure with various pores at 0.5-3 mu m. La(0.6)Ca(0.4)Co(0.8)Ru(0.2)O(3) exhibited a higher H(2)O(2) decomposition rate in KOH solution as opposed to that of ACP-derived La(0.6)Ca(0.4)CoO(3), which suggested an improved catalytic ability for oxygen reduction reaction (ORR). A similar behavior was observed during the ORR current-potential polarization using La(0.6)Ca(0.4)Co(0.8)Ru(0.2)O(3) supported on Black Pearl 2000 as a gas diffusion electrode. In addition, impedance spectra at the open-circuit voltage and selective cathodic overpotentials also confirmed a smaller charge-transfer resistance for La(0.6)Ca(0.4)Co(0.8)Ru(0.2)O(3). In galvanostatic measurements and lifetime evaluation, La(0.6)Ca(0.4)Co(0.8)Ru(0.2)O(3) demonstrated steady voltage profiles with negligible degradation. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3384665] All rights reserved.