Synthesis and characterization of graphene-cobalt phthalocyanines and graphene-iron phthalocyanine composites and their enzymatic fuel cell application

• Synthesis and characterization of GR-CoPc and GR-FePc composites.
• Oxidation of glucose at GR-CoPc/GOx/GCE.
• Reduction of oxygen at GR-FePc/GCE.
• Construction of glucose/O2 enzymatic fuel cell (EFC).
• The performance of EFC.

We prepared graphene (GR)-cobalt phthalocyanine (CoPc) and GR-iron phthalocyanine (FePc) composites by simple and facile chemical reduction method for enzymatic fuel cell (EFC) applications. The successful formation of the composites was confirmed by scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction and electrochemical methods. The as-prepared composites were used for the construction of glucose/O2 EFC. The anode of the EFC was prepared by immobilizing glucose oxidase (GOx) at the GR-CoPc composite modified glassy carbon electrode (GCE). GCE/GR-CoPc/GOx exhibited excellent electrocatalytic ability towards oxidation of glucose. In addition, the modified electrode showed appreciable stability, repeatability and reproducibility. GR-FePc composite exhibited superior electrocatalytic ability towards oxygen reduction reaction (ORR). A membraneless glucose/O2 EFC has been fabricated employing GCE/GR-CoPc/GOx and GCE/GR-FePc as anode and cathode respectively. The fabricated EFC offered a maximum power density of 23 μW cm−2 which is comparable with the previously reported EFCs and it exhibited appreciable stability and repeatability. From this study, we infer that GR based MPcs have great potential for the fabrication of EFCs.