Co-Doped Zeolite-GO Nanocomposite as a High-Performance ORR Catalyst for Sustainable Bioelectricity Generation in Air-Cathode Single-Chambered Microbial Fuel Cells.

High-performance cobalt (Co) nanoparticles supported on a zeolite-graphene oxide (1:2) matrix (catalyst Z2) are synthesized through a facile reduction method. In multipoint Brunauer-Emmett-Teller (MBET) surface area analysis, catalyst Z2 demonstrates a higher surface area compared with other synthesized catalysts, indicating the presence of a larger number of catalytic active sites, and supports outstanding ORR performance due to an improved electron-transfer rate and a higher number of redox-active sites. Furthermore, it is observed that catalyst Z2 is an excellent electrocatalytic material due to its low charge-transfer resistance and higher oxygen reduction reaction (ORR) activity. Herein, the electrocatalytic investigation suggests that catalyst Z2 at a potential of 483 mV and a reduction current of -0.382 mA displays a higher electrocatalytic performance and higher stability toward ORR compared with other synthesized catalysts and even the standard Pt/C catalyst. Also, when catalyst Z2 is applied as an air-cathode ORR electrocatalyst for a single-chambered microbial fuel cell (SC-MFC), the SC-MFC coated with catalyst Z2 generates the maximum power density of 416.78 mW/m2, which is 306% higher than that of SC-MFC coated with Pt/C (102.67 mW/m2). In fact, the longer stability and electronic conductivity have contributed to an outstanding ORR activity of the nanocomposite due to its porous surface morphology and the presence of the functional groups in the zeolite-GO support matrix. In brief, Co (cobalt) nanoparticles doped on a zeolite-GO (1:2) support matrix are promising cathode electrocatalysts in the practical application of MFCs and other related devices.