Two-dimensional materials-based cathodes for high-performance microbial fuel cells

Abstract

Microbial fuel cells (MFCs) have been considered an eco-friendly avenue for electricity production and concurrent water purificationtechnology. In MFCs, electrodes as the building blocks of MFCs play a significant role in determining the performances, thus an optimized selection of the suitable electrodes becomes crucial. Over the last decade, two-dimensional (2D) materials have emerged as potential electrodes to substitute precious metals such as platinum owing to their exceptional geometric structure, surface area, electrical conductivity, electronic properties. In this review, the potential benefits of 2D materials as cathodes to facilitate the reduction reaction in MFCs is discussed starting with biological redox reaction, physical chemistry of diverse 2D materials, and the respective MFCs performances. We cover from conventional graphene and layered double hydroxides (LDHs) as prototypical active material to emerging compounds such as, metal organic frameworks (MOFs), transition metal dichaldogenides (TMDs), and transition metal carbides (MXenes). The power density of 2D-based cathodes yields in the range of 50 – 2000 mW/m${}^2$, which stimulates further development. Additionally, some recent advances in the oxygen reduction reaction mechanism of 2D materials are also summarized. This insight may provide a deeper understanding for further designing highly catalytic materials and consequently improving the performances of MFCs. Finally, the future outlook and research direction are highlighted in further exploiting the uniqueness of 2D materials as cathodes for enhanced performances and reliability of MFCs to accelerate market adoption, paving the way for sustainable and renewable energy production.