Dual-physical-field coupling engineered MXene/polypyrrole hydrogel anode with transmembrane electron transfer enhancement strategy

Charge characteristics of materials significantly influence the growth of exoelectrogens and electron transfer in microbial fuel cells (MFCs). This study focused on regulating the charge distribution at the anode interface where electroactive bacteria attach. Here, an electro-low-temperature dual-field coupling strategy was employed to form MXene/PPy hydrogels, and their structural and charge distribution characteristics were thoroughly investigated. Experimental results demonstrated that under dual-field coupling, the protonated nitrogen content in the material increased significantly (24.2 % → 26.23 %), and the zero-charge potential decreased markedly (−0.430 V → −0.455 V), which enhanced the electrostatic attraction of the anode interface to electroactive bacterial communities. High-throughput sequencing and PICRUSt analysis revealed preferential enrichment of electroactive species (69.26 % → 85.84 %), leading to more efficient direct extracellular electron transfer and a 1.5-fold increase in MFC power density (reaching 3.51 W/m2). Theoretical calculations further confirmed that the functional enrichment of protonated nitrogen (-N+ = , -NH+) facilitated uptake electrons from FePc and accelerated electron transfer efficiency (EET). This study emphasizes the optimization of charge distribution and interfacial electron flow pathways (Fe atom in the FePc → Nppy → Cppy → MXene → CF electrode) at the MXene/PPy anode under dual-field coupling, highlighting the potential of this modification strategy in biofunctional materials.