Graphitic carbon nitride/carbon brush composite as a novel anode for yeast-based microbial fuel cells

A biocompatible graphitic carbon nitride (g-C₃N₄) was prepared on the surface of carbon brush fiber (CB) via a facile one-step preparation method. The prepared g-C₃N₄ formed a composite with the carbon brush's fibers (g-C₃N₄@CB), as shown from the XRD analysis. The g-C₃N₄@CB was used as an anode in a yeast-based microbial fuel cell (MFC), and demonstrated an outstanding performance compared to plain CB. An anode potential of −0.27 V “vs. Ag/AgCl” and an open-circuit voltage of 0.77 V was obtained in the case of the composite electrode, compared to −0.1 V vs. Ag/AgCl and 0.62 V, respectively, in the case of the CB. The cell using the composite electrode demonstrated a maximum power of 772 mWm⁻², which is twelve times that obtained using the CB. The outstanding performance of the composite electrode can be credited to the biocompatibility of the composite anode and its roughness, which improved the yeast biofilm formation and decreased the ohmic resistance. This is the first report involving the application of g-C₃N₄ in a yeast-based MFC, and it demonstrated promising results which can be used for other types of MFCs.