Temperature-depended Cu0.92Co2.08O4 modified activated carbon air cathode improves power output in microbial fuel cell

Abstract

Temperature-depended Cu0.92Co2.08O4 catalyst doped activated carbon (AC) air cathode for microbial fuel cells (MFCs) was studied for the first time. The Cu0.92Co2.08O4 was compounded via hydrothermal method followed by calcinated at 400, 500, 600 and 700 °C, respectively. The maximum power density (MPD) with the catalyst calcinated at 600 °C was 1895 mW m−2, 113% higher than the control. Besides, the resistances including total resistance and charge transfer resistance were remarkably decreased compared to the bare AC. Tafel curve also showed the fastest electro-transfer kinetics with exchange current density of 2.38347 × 10−3 A cm−2, 4.2 times higher than the bare. The oxygen reduction reaction pathway of Cu0.92Co2.08O4 was via four electrons. The mechanism of improved oxygen reduction reaction performance of Cu0.92Co2.08O4 was researched by XRD, SEM, TEM and XPS. Thus Cu0.92Co2.08O4 would be a promising electrocatalyst alternative to Pt for the ORR in microbial fuel cell.