Activated carbon-supported multi-doped graphene as high-efficient catalyst to modify air cathode in microbial fuel cells

It is difficult to apply microbial fuel cells (MFCs) basing on activated carbon air cathode in practical application because of the low efficiency of oxygen reduction reaction. Thus, exploring high-efficient catalyst to improve the cathode performance is of emergent significance. Herein, we synthesize an activated carbon-supported Fe-Ag-N multi-doped graphene as the air cathode catalyst in MFCs via a simple preparation and calcination of Fe-Ag prussian blue analogues. As proved, the designed catalyst contributes to the decrease of the cathode's diffusion resistance and charge transfer resistance; mean-while it immensely promotes the kinetics towards ORR by accelerating the migration of electron from the encapsulated bimetals to the surrounding carbon structure, indicating that the deposit of multi-doped graphene catalyst reinforces the cathode's conductivity and expedites the electron transfer process. The output power performances indicate that a highest maximum power density reaches up to 1956.45 mWm(-2), which is 7 times higher than that of the control, foreboding the catalyst's potential application in MFCs. (C) 2019 Elsevier Ltd. All rights reserved.