A novel MXene-coated biocathode for enhanced microbial electrosynthesis performance

Microbial electrosynthesis (MES) is a promising bioelectrochemical technology for the simultaneous consumption of carbon dioxide/bicarbonate and generation of useful chemical products. However, low current densities and a narrow product range with an inadequate production rate are bottlenecks in current MES technologies. In response to this, cathode modification has been suggested as a strategy to improve MES performance. Titanium carbide (Ti₃C₂T_X MXene), a recently discovered 2D material, has a multilayered structure, high surface area, and excellent conductivity, which are prerequisites for an excellent cathode material. In this study, 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. Scanning electron microscopy, electrochemical, and microbial community analyses revealed that the MXene-coated cathode promoted the formation and enrichment of biofilm. Thus, these results demonstrate that MXene@CF is a promising cathode material for MES.