The influence of ZIF-L in a microbial fuel cell (MFC) cathode for oxygen reduction reaction (ORR)

Microbial fuel cells (MFCs) utilize the metabolic activities of microorganisms, through which the chemical energy is directly converted into electrical energy. Bacteria produce electrons by means of oxidation of organic/inorganic substrates within the MFCs. Metal organic frameworks (MOFs) that are porous coordination polymers have gained much interest in the field of efficient catalysts due to their unique characteristics. The utilization of MOF catalysts for oxygen reduction reaction (ORR) in the MFC cathode is one of the most remarkable research areas in material science. MOF (zeolitic imidazole framework-leaf like, ZIF-L) decorated cathode system was employed for the first time in MFC to monitor the improvement in performance by taking advantages of both electrocatalytic activity and porosity of MOFs for the utilization of bioelectrons for ORR. Analysis of ORR performance of ZIF-L/carbon black (CB) composite cathode demonstrated that ZIF-L containing cathode system had an improved ORR activity compared to MFC cathode materials in the literature. The remarkable current density value of 2.1 mA cm^-2 and the maximum power density value of 1,462 mW m^-2 at room temperature revealed that ZIF-L decorated cathode is an excellent alternative for efficient reduction of oxygen in MFCs.