Anthraquinone-2-sulfonate immobilized to conductive polypyrrole hydrogel as a bioanode to enhance power production in microbial fuel cell

•Anthraquinone-2-sulfonate was covalently grafted on conductive polypyrrole hydrogel.•CPH/AQS enhanced biofilm formation.•CPH/AQS reduced charge transfer resistance.•CPH/AQS increased power density in MFC.

In this study, anthraquinone-2-sulfonate (AQS), a redox mediator, was covalently bound to conductive polypyrrole hydrogel (CPH) via electrochemical reduction of the in-situ-generated AQS diazonium salts. The porous structure and hydrophilic surface of this CPH/AQS anode enhanced biofilm formation while the AQS bound on the CPH/AQS anode worked as a redox mediator. The CPH/AQS bioanode reduced the charge transfer resistance from 28.3 Ω to 4.1 Ω while increased the maximum power density from 762 ± 37 mW/m2 to 1919 ± 69 mW/m2, compared with the bare anode. These results demonstrated that the facile synthesis of the CPH/AQS anode provided an efficient route to enhance the power production of microbial fuel cell (MFC).