Mesoporous LaFeO3 perovskite as an efficient and cost-effective oxygen reduction reaction catalyst in an air cathode microbial fuel cell

Abstract

Microbial fuel cells (MFCs) produce renewable energy from organic matter in presence of electrochemically active anaerobes at the anode and cathode oxygen reduction reaction (ORR). The ORR catalyst is pivotal for power generation and the overall cost of constructing an MFC. This study uses a synthesized novel LaFeO3 perovskite electrocatalyst as an alternative to the conventional Pt/C cathode catalyst which enhances ORR activity in a pH-neutral electrolyte. LaFeO3-based air cathode MFC produced 726.43 mWm−2 of maximum power density and is comparable to the commercial Pt/C catalyst i.e., 775 mWm−2. Furthermore, it has achieved 2.3 mAm−2 of the maximum current density and 556 mV of voltage. The improved catalytic activity of the synthesized LaFeO3 is associated with a large number of active sites, oxygen vacancies, and its mesoporous nature. Therefore, LaFeO3perovskite was able to catalyze ORR with an electron transfer of 3.8 in a neutral medium which is close to superior indirect four-electron pathways. It is highlighted that LaFeO3 perovskite iscost-effectiveand has comparable electrochemical properties with Pt/C which is evident in its scale-up potential of MFCs for green energy synthesis.