Polyaniline interweaved iron embedded in urea–formaldehyde resin-based carbon as a cost-effective catalyst for power generation in microbial fuel cell

Abstract

• Iron-containing urea–formaldehyde (Fe-UF) resins were used as precursors. • Polyaniline (PANI) interweaved Fe-UF was pyrolyzed for the synthesis of PANI@Fe/NC. • Polyaniline interweaving improved the conductivity, charge transfer resistance, and ORR activity over Fe/NC. • Among the catalysts, PANI@Fe/NC achieved the highest power output of 637.53 mW m −2 . Microbial fuel cells (MFCs) have emerged as promising renewable electricity generation devices. However, the technology is challenged by poor durability, sluggish oxygen reduction reaction (ORR) kinetics, and high capital cost. Herein, we developed highly efficient and inexpensive electrocatalysts for commercially viable MFCs. The performance of the fabricated air-cathodes (NC, Fe/NC, and PANI@Fe/NC) was systematically evaluated in single-chamber MFCs with activated sludge as inoculum. Fe containing urea–formaldehyde (UF) resins were interweaved with polyaniline to enhance overall conductivity, charge transfer, and power generation in MFCs. PANI interweaved resins exhibit nanofiber aggregation, which on pyrolysis at 800℃ result in unique coralline-like short rods attributing to the large surface area of PANI@Fe/NC. The electrochemical analysis highlighted the superior performance of PANI@Fe/NC with a peak reduction current of −0.214 mA, charge transfer resistance (Rct) of 132.5 Ω, and improved ORR activity. PANI@Fe/NC achieved the highest power output (637.53 mW m -2 ) achieved by PANI@Fe/NC was 36.25% higher than conventional 10 wt% Pt/C (467.92 mW m -2 ). A high current density of 1943.71 mA m -2 compared to 1665.18 mA m -2 for Pt/C is indicative of the significant improvement in the catalytic ability of PANI@Fe/NC. This could be attributed to diverse Fe and N states in the carbon composites and the large surface area available for high active site density. The outcomes suggest that this novel and cost-effective cathode catalyst could be used for long-term fuel cell and related applications.