Enhancing performance of microbial fuel cell by using graphene supported V₂O₅-nanorod catalytic cathode

Highlights: • In support with graphene (rGO), V₂O₅-NRs showed excellent ORR kinetics. • V₂O₅/rGO cathode enhanced power output with superior wastewater treatment in MFC. • Power density in MFC using V₂O₅/rGO was found higher than MFC with Pt-C cathode. • Cathode fabrication cost using V₂O₅/rGO catalyst was found much lower than Pt-C. - Abstract: Cathodes were fabricated around stainless steel wire mesh current collector, using vanadium pentoxide nanorods (V₂O₅-NRs) as catalyst supported with reduced graphene oxide (rGO) and Vulcan XC, for application in microbial fuel cell. Cyclic voltammetry analysis showed multiple redox current peaks of V₂O₅-NRs under applied potential range, revealing superior electrocatalytic activity. Power density enhanced from 384 ± 45 mW/m² for MFC using V₂O₅/Vulcan XC cathode to 533 ± 37 mW/m² for MFC using V₂O₅/rGO cathode; whereas MFC using catalyst free cathode fabricated with rGO and Vulcan XC produced significantly less power density of 95 ± 9.9 and 75 ± 7 mW/m², respectively. In addition, MFC using V₂O₅/rGO cathode demonstrated slightly higher power density than that obtained from MFC using 10% Pt-carbon cathode (512 ± 51 mW/m²). Coulombic efficiency and chemical oxygen demand removal of 37.5 ± 1.36% and 85.02 ± 1.46% in MFC using V₂O₅/rGO cathode was found to be highest among all MFCs. Noteworthy improvement in catalytic activity of low-cost V₂O₅-NRs catalyst enfolded with graphene is demonstrated, resulting in higher power output and organic matter removal in MFC. Higher power generated by MFC using low cost V₂O₅/rGO cathode, compared with costly platinum, makes it suitable option for scale-up of MFCs.