[SCAN] Electrode (anode/cathode) modification for enhancing bioelectrochemical systems performance

Title: Electrode (anode/cathode) modification for enhancing bioelectrochemical systems performance

Speaker: Khurram Tahir

Abstract: In recent years, the modification of electrode materials for enhancing the power generation of bioelectrochemical systems (BESs) such as microbial fuel cell (MFC) and microbial electrosynthesis system (MES) has attracted considerable attention. For improving BES performance, electrode modification was proposed and evaluated for the electricity generation via anode in MFC, and useful products formation via cathode in MES. In one of the studies, a novel MXene-coated carbon felt electrode (MXene@CF) was fabricated and investigated for use in MES. The modified cathode material exhibited excellent current generation and volatile fatty acid production. The availability of more active sites and sufficient space for microbial growth enhanced the mass transfer between the microbes and the substrate, resulting in a 1.6-, 1.1-, and 1.7-fold increase in the concentration of acetic, butyric, and propionic acid, respectively, compared to uncoated carbon felt. In the study involving MXene structure coated on a cost-effective biochar substrate electrode, improved electrical conductivity, increased charge transfer efficiency, and selective microbial enrichment characteristics was observed, resulting in a 2.3 -fold increase in cathodic current production in comparison to the uncoated biochar. In MFC study, a conventional carbon felt (CF) electrode was modified by NiFe₂O₄ (NiFe₂O₄@CF), MXene (MXene@CF), and NiFe₂O₄-MXene (NiFe₂O₄-MXene@CF) using facile dip-and-dry and hydrothermal methods. In these modified CF electrodes, the electrochemical performance considerably improved, while the highest power density (1385 mW/m²), which was 5.6, 2.8, and 1.4 times higher than those of CF, NiFe₂O₄@CF, and MXene@CF anodes, respectively, was achieved using NiFe₂O₄-MXene@CF. The improved performance could be attributed to the low charge transfer resistance, high conductivity and number of catalytically active sites of the NiFe₂O₄-MXene@CF anode. Therefore, these results suggest that combining the favorable properties of composite materials such as NiFe₂O₄- MXene@CF anodes could improve MFC system. Taking together, MXene based materials can effectively improve both MFC and MES performance and could be used to fabricate novel electrodes for renewable energy-related applications such as BES.