The Production of rGO – MXene / P34HB Composite Membranes via Solution Casting and Electrospinning: A Comparison of Their Structural Properties and Performance in Microbial Fuel Cells

ABSTRACT This study, biodegradable poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) (P34HB) based composite membranes reinforced with reduced graphene oxide (rGO)/MXene hybrid nanofillers (0.25–2.5 wt%) for microbial fuel cell (MFC) applications were prepared by solution casting and electrospinning methods. The effects of hybrid nanofiller loading and preparation methods on membranes' morphological, mechanical, thermal, proton transport, biodegradation, and electrochemical characteristics were examined. The co‐incorporation of MXene and rGO into the P34HB membranes improved thermal stability and proton conductivity. These improvements were attributed to the hydrophilic surface functional groups of MXene and the conductive network formed by rGO. Membranes with 1.5 wt% rGO–MXene performed the best of all compositions; they had the largest water absorption, improved proton transport, and favorable activation energy values. Due to their porous structures and improved hydration capacities, nanofiber membranes exhibited higher proton conductivity and biodegradability compared to cast membranes. MFC performance tests revealed that using hybrid nanofillers significantly improved electrochemical performance compared to pure membranes. Nanofiber membrane containing 1.5 wt% rGO–MXene delivered highest power density of 477 mW m −2 , along with a coulombic efficiency of 27.7% and COD removal of 91%–93%, demonstrating efficient electron transfer and substrate utilization. These findings provide a promising strategy for the development of sustainable and high‐performance proton exchange membranes for MFC systems.