Hybrid binuclear-cobalt-phthalocyanine as oxygen reduction reaction catalyst in single chamber microbial fuel cells

• Bi-CoPc/C had better performance than normal CoPc/C.
• Bi-CoPc/C hybrided with NiO and CoO substantially enhanced ORR in SCMFCs.
• Integration of NiO and CoO to Bi-CoPc increased the O and N functional groups.
• Power density of SCMFC with Bi-CoPc–NiO/C cathode was 400 mW m−2, close to Pt/C.

A novel hybrid binuclear-cobalt-phthalocyanine (Bi-CoPc) is developed as the cathode catalyst to replace the costly platinum (Pt) in single chamber microbial fuel cells (SCMFCs). Bi-CoPc/C is integrated with metal oxides (NiO and CoO) to form macrocyclic complex for enhanced oxygen reduction rate (ORR). The characteristics of hybrid catalysts (Bi-CoPc/C–CoO and Bi-CoPc/C–NiO) are compared with Co-contained catalysts (CoPc/C and Bi-CoPc/C) and metal oxide catalysts (NiO and CoO). The increase in O and N functional groups indicates the benefits of NiO and CoO to the cathode catalysts. The cyclic voltammetry (CV) shows the reduction peak for Bi-CoPc/C–NiO and Bi-CoPc/C–CoO at −0.12 V and −0.22 V, respectively. The power densities (368 mW m−2 and 400 mW m−2) of SCMFCs with Bi-CoPc/C–CoO and Bi-CoPc-NiO/C are the highest among the cathodes tested, and close to that of Pt (450 mW m−2). This study demonstrates that hybrid Bi-CoPc/C with metal oxides has a great potential as a cost-effective catalyst in MFCs.