Cost-effective sewage-powered microbial fuel cells with nitrogen-doped cobalt carbon nanofiber cathodes and biomass-derived graphitized anodes.

Abstract

This study presents the design and performance of microbial fuel cells (MFCs) utilizing sewage water as a renewable source for electricity generation. The proposed MFCs employ an air-cathode, single-chamber configuration that harnesses atmospheric oxygen as the electron acceptor, eliminating the need for consumable electron acceptor chemicals. Unlike traditional systems, no external microorganisms are introduced; instead, indigenous microbial communities present in sewage are utilized as efficient biocatalysts. The anode is constructed from graphitized corncob, a biomass-derived material that surpasses conventional anodes such as carbon cloth and carbon paper, achieving power densities of 450 ± 15 mW/m², outperforming 120 ± 7 and 105 ± 5 mW/m² of conventional anodes. For the cathode, N-doped and Co-incorporated carbon nanofibers (CNFs) are employed, representing a cost-effective alternative to precious metal-based catalysts. This cathode material demonstrates superior electrochemical performance, producing a power density of 750 ± 17 mW/m², a notable improvement over the Pt/C cathode. Optimization studies identified 5 wt% CNFs as the ideal loading for the cathode. These findings underscore the viability of this MFC configuration in harnessing sewage water for sustainable electricity generation while reducing costs and reliance on precious metals.