Carbon‐supported perovskite oxides as oxygen reduction reaction catalyst in single chambered microbial fuel cells

Abstract BACKGROUND: Pt‐free cathodic catalyst is needed for microbial fuel cells (MFCs). Perovskite‐type oxide could be a substitute for Pt because it has been proved to be a highly active and low‐cost oxygen reduction catalyst in chemical fuel cells. RESULTS: A nano‐sized La 0.4 Ca 0.6 Co 0.9 Fe 0.1 O 3 perovskite‐type oxide on a carbon support (LCCF/C) was prepared and tested for its performance and stability (15 cycles) in MFCs. An exchange current density of 7.030 × 10 −5 (A cm −2 ) was obtained with fresh LCCF/C cathode and is increased to 7.438 × 10 −5 (A cm −2 ) after 15 cycles operating in MFCs. A power density of 405 mW m −2 was achieved with the LCCF/C cathode at the 2nd cycle which was between those of Pt/C (560 mW m −2 ) and C (339 mW m −2 ) cathodes. At the end of the 15th cycle, the lowest decay (due to biofouling) rate on the open circuit voltage (2%) and the maximum power density (15%) were observed with LCCF/C cathode compared with those of Pt/C (4%, 17%) and C (22%, 69%) cathodes, respectively. CONCLUSIONS: This study demonstrated that perovskite‐type oxide on carbon support catalysts could be a potential substitute for Pt for cathodic oxygen reduction reaction (ORR) in air‐cathode MFCs. © 2012 Society of Chemical Industry