Microbial fuel cells with enhanced bacterial catalytic activity and stability using 3D nanoporous stainless steel anode

The activity and stability of the anode biofilm control the produced power by microbial fuel cells (MFCs). In this study, 3D nanoporous stainless steel (SS) was used as an anode material in MFCs to enhance both the biofilm growth and its adhesion to the support electrode, which would improve the catalytic activity and stability of MFCs anode biofilm. The effect of varying the annealing atmosphere on the SS performance was studied and correlated with the change in the oxidation states of the surface elements. Annealing the SS, before or after anodization, is found to have a major contribution to the biofilm growth due to the presence of more biocompatible components at the SS surface. The high roughing of the SS via anodization as well as the formation of the 3D nanoporous film has a huge contribution to the biofilm stability, especially when the MFC is generating high power. The best SS anode annealed in O-2 atmosphere produced 430 mW/m(2) compared to 0.01 mW/m(2) produced by the as-received SS. (C) 2020 Elsevier Ltd. All rights reserved.