Cobalt - Iron phthalocyanine supported on carbide - Derived carbon as an excellent oxygen reduction reaction catalyst for microbial fuel cells.

Abstract A highly active cathode catalyst for oxygen reduction reaction (ORR) is the key to the efficient production of renewable energy from waste resources using microbial fuel cells (MFCs). Among non-noble metal catalysts, transition metals have shown promising activity towards ORR. In this study, synergy between cobalt (Co) and iron phthalocyanine (FePc) supported in carbide-derived carbon (CDC) is demonstrated in Co-FePc/CDC as the catalyst for ORR. Notably, CDC is synthesized from waste heating rods of a high temperature furnace. Several physicochemical characterization techniques, such as x-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and Raman spectroscopy are used to confirm the successful doping of Co-FePc in the graphitic CDC. The polarization study using rotating disc electrode reveals Co-FePc/CDC to be a more efficient catalyst towards ORR than Co/CDC, the former material promoting a 4 electrons-pathway with the negligible formation of the intermediate H 2 O 2. The cyclic voltammetry (CV) analysis showed highly consistent multiple redox peaks with a relatively smaller overpotential over multiple CV cycles. As a result of the enhanced ORR kinetics, the Co-FePc/CDC-based MFC recovered a peak power density of 1.57 W/m2 with the coulombic efficiency of 43.6% from the acetate-based synthetic wastewater. Furthermore, the MFC demonstrated an excellent chemical oxygen demand removal efficiency of 86%. Graphical abstract Image 1 Highlights • CDC prepared from waste SiC heating rods was used as a support for Co-FePc. • Physical characterizations revealed a synergy between CDC and Co-FePc. • Co-FePc/CDC showed an excellent ORR characteristics. • Co-FePc/CDC cathode catalyst-based MFC recovered a power density of 1.5 W/m2. • MFC simultaneously demonstrated an excellent COD removal efficiency of 86%. [ABSTRACT FROM AUTHOR]