Regulation of Stainless Steel Electrode Characteristics through Thermal Oxidation at Various Temperatures Induces Different Microbial Electrochemical Performances

The impact of thermal treatment at various temperatures on the properties of stainless steel (SS) anodes and subsequent bioelectricity generation is investigated in this study. It is observed that thermal oxidation at different temperatures significantly affects the characteristics of SS anodes. SS electrodes treated at 900 °C resulted in the best bioelectricity generation of Shewanella oneidensis MR-1 with a peak current density and power density of 0.36 ± 0.08 A m–2 and 1.15 ± 0.02 W m–2, respectively. Both experiments and molecular dynamics simulations indicate that such improvements may be due to not only the good biocompatibility of heat-treated SS electrodes but also the enhancement of direct extracellular electron transfer of S. oneidensis MR-1 to the anode. Moreover, using a home-made microfluidic device, we find that the biofilms on heat-treated SS electrodes exhibit better stability compared to unaltered ones. This study provides theoretical support for the application of SS electrodes in microbial electrochemistry technology