Research on the impact of polydopamine hydrogel electrodes with various doping methods on the performance of microbial fuel cells.

Abstract

Microbial fuel cells (MFCs) have attracted considerable interest as a promising bioelectrochemical technology for directly converting chemical energy into electrical energy. However, their performance remains limited by the properties of anode materials and their interactions with microbial communities. In this study, PPy-MXene/PDA and PDA-PPy-MXene composite hydrogel electrodes (PMP and PPM) were fabricated on a conductive carbon felt substrate to systematically evaluate the influence of different PDA doping strategies on electrode performance. The PMP electrode exhibited a maximum power density of 3.62 W/m², which represented a 34.6% increase compared to the PPM electrode (2.69 W/m²). Moreover, the protein content on the PMP electrode reached 38.05 ± 4.88 mg/cm², 3.79 times higher than that on the PPM electrode (10.05 ± 3.05 mg/cm²). High-throughput sequencing of the 16S rRNA gene revealed that the relative abundance of Geobacter on the PMP electrode surface reached 73.66%, significantly higher than the 51.17% observed on the PPM electrode. These results are attributed to the PDA doping method involving secondary deposition on the electrode surface. This method optimizes the electron transfer pathways and significantly enhances the electrode's conductivity and electrochemical activity by altering the surface roughness of the electrode and increasing the content of hydrophilic functional groups. Consequently, it significantly promotes the enrichment of electroactive microorganisms and improves the efficiency of extracellular electron transfer. This study optimized PDA doping strategies to significantly enhance the electrochemical performance of MFCs, providing new insights and approaches for the rational design of high-performance bioelectrochemical electrodes.