Enhanced Stability and Performance of Soil Microbial Fuel Cells Using MoCoO₄ Nanowire Decorated Carbon Felt Electrodes

Abstract

The depletion of energy resources due to increasing human demands has become a growing concern; thus, developing sustainable energy technologies is essential. One innovative approach is soil microbial fuel cells (SMFCs), which are affordable and carbon-neutral bioremediation energy systems for polluted lands. Carbonaceous materials (CMs) are the most used materials as anodes for SMFCs, as they have reasonable conductivity, biocompatibility, and high surface area. However, decorating the CMs with metal oxide increases their specific surface area, enhancing the electrochemical behavior of the anode and enriching the exoelectrogenic microbial community. Although decorating the anodes with metal oxides, such as Co 3 O 4 , MnO 2, and Fe 2 O 3 , has enhanced the SMFCs' performance, they suffer instability through metal oxide leakage under operation conditions 1,2 . Thus, more stable metal oxides, such as bimetallic nanostructure oxides, should be investigated as anodes for SMFCs. These oxides are also expected to enhance the electron transfer rate, conductivity, and the exoelectrogenic microbial community. In this work, carbon felt (CF) is decorated with MoCoO 4 nanowires using hydrothermal synthesis. The MoCoO 4 nanowires were then coated with an electropolymerized conductive polymer as a carbon source to achieve better stability and electrical conductivity. The SEM images confirmed the formation of a homogeneous layer of MoCoO 4 nanowires, and the XRD and XPS results demonstrated their crystal structure and chemical composition. A significant improvement in the growth/adhesion of the microbial layer was observed due to the increase in surface area of the roughened electrodes, shown in SEM images, which, in turn, increased the power produced by the SMFC. Accordingly, the SMFC with maximum power was produced using MoCoO 4 @CF anode (87 mW/m 2 at 178.5 mA/m 2 ), with a power double that produced by the blank GF(44 mW/m 2 at 100 mA/m 2 ) and higher than that previously reported in the literature using Cobalt oxide nanoflakes interweaved with polyaniline (70 mW/m 2 at 143 mA/m 2 ) 1 . The SMFC that employed MoCoO 4 @CF electrodes maintained high power after fifty days of being in the soil setup, indicating the stability of the nanostructure. References: S. K. Dhillon, J. Dziegielowski, P. P. Kundu, and M. D. Lorenzo, RSC Sustain. , 1 , 310–325 (2023). D. Nosek, T. Mikołajczyk, and A. Cydzik-Kwiatkowska, International Journal of Environmental Research and Public Health , 20 , 2580 (2023).

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Identifiers

DOI

10.1149/ma2025-01482485mtgabs

Journal

ECS Meeting Abstracts

Year

2025