Integrating MXene with carbon dots modified bacteria as hybrid biofilm for photo-assisted microbial fuel cells

The development of microbial fuel cells (MFCs) places a high demand on the building of high-performance exoelctrogenic biofilm. In this study, by the electrostatic self-assemble between Ti₃C₂T_x MXene and carbon dots-modified exoelctrogenic bacteria (B@CDs), a MXene-based hybrid biofilm has been developed for MFCs. The modification of positively-charged CDs onto bacterial surface not only builds the bridge between negatively-charged MXene and bacterial cells for the construction of hybrid biofilm, but also endows the photoelectric conversion ability for the realization of multiple energy transfer in hybrid biofilm. Meanwhile, the MXene network paves high-speed pathways for electron transfer during microbial catalytic oxidation and photoelectric conversion processes. As a result, the MFC with this MXene-based hybrid biofilm has achieved a maximum power density of 7518.5 mW/m² in darkness, which increased to 9396.1 mW/m² under light illumination. This work not only offers a good start for the development of MXene-based hybrid biofilm, but also upgrades the performance of photo-assisted microbial fuel cells to a high level for highlighting their application potential as the green and sustainable energy source.