Carbon supported cobalt oxide nanoparticles–iron phthalocyanine as alternative cathode catalyst for oxygen reduction in microbial fuel cells

► Cobalt oxide–iron phthalocyanine was used to replace platinum as the cathode catalyst in the microbial fuel cell. The maximum power density of 654±32mWm−2 is achieved from the C–CoOx–FePc cathode, which is 37% higher than the power density of C–FePc. The voltage output of the MFC only decreases to 85% of its initial voltage after 50 cycles, suggesting the acceptable long-term stability. The high cost and limited resources of precious metals as oxygen reduction catalysts (ORR) hindered the widespread use of microbial fuel cells (MFCs) in practice. Here, the feasibility of metal oxide assisted metal macrocyclic complex was investigated as a catalyst for ORR in an air-cathode MFC. Electrochemical results revealed that cobalt oxide (CoOx) incorporation increased the ORR activity of iron phthalocyanine (FePc). In MFCs, the maximum power density of 654±32mWm−2 was achieved from the C–CoOx–FePc cathode, which was 37% higher than the power density of carbon supported FePc (C–FePc). The voltage output of the MFC only decreased to 85% of its initial voltage after 50 cycles, suggesting that the synthesized catalyst showed acceptable long-term stability. The voltage drop partially resulted from the covering of biofilm on the catalyst layer. This work provided a potential alternative to Pt in MFCs for sustainable energy generation.