Enhanced hydrogen production in microbial electrolysis cells through a magnetically induced electroactive anode biofilm

[Display omitted] •A novel electron transfer strategy was introduced using magnetic media and field.•Magnetic media (MM) was successfully synthesized using cost-effective biochar.•Magnetic fields (MF) formed artificial biofilms with MM and electroactive bacteria.•H2 production increased 1.8-fold after applying this novel electroactive biofilm.•In-depth microbial analysis uncovered key links between bacteria and H2 efficiency. This study investigates how the simultaneous application of magnetic fields (MFs) and magnetic media (MMs) enhances microbial electrolysis cell (MEC) performance by promoting artificial biofilm formation on the anode surface. By incorporating biochar coated with magnetizable particles as the MM and applying a 150 mT MF, the integrated MM + MF system enhances microbial activity and provides an improved electrochemical environment. This engineering approach significantly increased hydrogen production, achieving a 1.8-fold improvement over the control reactor by promoting the growth of electrochemically active bacteria (EABs) within the artificially formed biofilm. These findings indicate that the integration of MF and MM enhances the performance MEC by facilitating the artificial formation of electroactive biofilms, thereby addressing the limitations of conventional anode designs. This study also thoroughly investigates changes in microbial community structure and identifies key drivers that contribute to improved system efficiency. Therfore, this approach offers a cost-effective strategy for advancing bioelectrochemical systems, particularly in microbial fuel cells (MFCs), microbial electrosynthesis (MES), and wastewater treatment applications, as well as related electrode technologies such as capacitive deionization (CDI) and electrochemical desalination.