The Influence of Active Carbon Supports Toward the Electrocatalytic Behavior of Fe₃O₄ Nanoparticles for the Extended Energy Generation of Mediatorless Microbial Fuel Cells

Magnetite (Fe₃O₄) nanoparticles anchored over the different active carbon supports were developed by a simple wet solution method. The developed nanostructures were magnetically self-assembled over the electrode surface and exploited as anode catalysts in mediatorless microbial fuel cells (MFC). The morphological characterizations revealed that 3∼8-nm-sized Fe₃O₄ nanoparticles were homogeneously anchored over the different carbon matrices and the obtained diffraction patterns ensured the cubic inverse spinel structure of prepared Fe₃O₄ nanoparticles. The morphology, size, and structure of Fe₃O₄ nanoparticles anchored over the different active carbon supports were maintained identical, and the influence of active carbon support toward the effectual MFC performances was evaluated under various electrochemical regimes and conditions by using Escherichia coli as a catalytic microorganism. The electrochemical characterizations revealed that carbon nanotube (CNT)-supported Fe₃O₄ nanoparticles exhibited lower charge transfer resistance and high coulombic efficiency in comparison with the graphene and graphite nanofiber-supported composites. Among the studied anode catalysts, Fe₃O₄/CNT composite exhibited the maximum MFC power density of 865 mW m⁻² associated with excellent durability performances, owing to the specific interaction exerted between the microorganisms and the Fe₃O₄/CNT composite. Thus, the binder-free electrode modification process, mediatorless environment, rapid electron transfer kinetics, high power generation, and long durability performances achieved for the developed system paved futuristic dimensions for the high performance MFCs.