3D porous carbon materials in situ-embedded with Fe3C/Fe nanoparticles as high-performance anode electrocatalysts of microbial fuel cells

The power output of microbial fuel cells (MFCs) depends on the biofilm activity on the anode and the electron transfer efficiency between electrode and microbes. Therefore, enhancing the biocompatibility and conductivity of the anode is the key to improving MFCs performance. In this work, a series of porous carbon (PC) materials with core-shell nanoparticles (carbon shell, Fe3C/Fe core), denoted as Fe3C/Fe@PCX, were prepared using a nitrate-assisted polymer bubbling method by pyrolyzing polyvinylpyrrolidone (PVP) with ferric nitrate (Fe (NO3)3). These materials were coated on carbon felt (CF) to serve as the modified anode for the MFCs. An optimal foaming agent dosage led to a porous structure (Fe3C/Fe@PC1.8), giving the anode excellent surface morphology, conductivity, and biocompatibility, thereby enhancing the enrichment of dominant electroactive microorganisms and biofilm activity, and significantly improving electron transfer efficiency and MFC power output. The anode resistance (Ranode) of the MFCs equipped with the Fe3C/Fe@PC1.8-CF is only 131.50 S2, significantly lower than that of the control group (2449.00 S2). The maximum output voltage reaches 0.687 V, and the power density is 4.90 W/m2, which are 1.46 and 2.28 times greater than the control group, respectively. The superior performance of the modified anode demonstrates significant potential for application in high-performance MFCs.