Graphene/poly(3,4-ethylenedioxythiophene)/Fe3O4 nanocomposite – An efficient oxygen reduction catalyst for the continuous electricity production from wastewater treatment microbial fuel cells

• Ternary composite comprising graphene, polymer and Fe3O4 rods are developed.
• The conductive PEDOT bridges rGO sheets and Fe3O4 nanorods.
• Growth and formation mechanisms of rGO/PEDOT/Fe3O4 are elucidated.
• Large oxygen adsorption sites of composite improve the ORR kinetics.
• High MFC power and excellent durability are obtained for ternary composite.

The ternary composite comprising reduced graphene oxide (rGO), poly(3,4-ethylenedioxythiophene) (PEDOT) and iron oxide (Fe3O4) nanorods is developed and its substantial contribution toward the green energy generation of air cathode microbial fuel cells (ACMFC) as an efficient oxygen reduction reaction (ORR) catalyst is evaluated by using the different electrochemical techniques under various regimes and conditions. The effectual distribution of needle like and cubic inverse spinel structured Fe3O4 nanorods over the PEDOT enveloped graphene sheets are elucidated from the electron micrographs and the growth and composite formation mechanisms of Fe3O4 and rGO/PEDOT/Fe3O4, respectively, are enunciated from the detailed structural characterizations. The extended surface area, high electrical conductivity, and large oxygen adsorption sites of rGO/PEDOT/Fe3O4 nanocomposite facilitate the excellent ORR kinetics, which yields the maximum ACMFC power density with the superior durability of more than 600 h. Thus the proposed strategy extends a new approach in bringing the advantages of active carbon, conductive polymer and nanomaterials in a single tool, which constructs the prepared ternary composite as a potential ORR contender to the commercially available catalysts.

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