Microbially-reduced graphene scaffolds to facilitate extracellular electron transfer in microbial fuel cells

► This study demonstrates a simple method to decorate the anode biofilm of an microbial fuel cell (MFC) with graphene. ► The reduced graphene was obtained via bacterial extracellular respiration in the anode. ► The graphene scaffolds increased the actual accessible active exoelectrogens. ► The maximum power density and columbic efficiency was increased by 32% and 80%, respectively. ► The findings provided a potential alternative to increase MFC energy output.