Vitamin-C-enabled reduced graphene oxide chemistry for tuning biofilm phenotypes of methylotrophs on nickel electrodes in microbial fuel cells.

This study reports the use of multi-layered reduced graphene oxide (rGO) coating on porous nickel foam (NF) electrodes for enhancing biofilm growth of Rhodobacter Sphaeroides spp fed with methanol in microbial fuel cells (CH ₃ OH-MFCs). Electrochemical methods were used to assess the methylotrophic activity on rGO/NF electrodes. The power density and current density offered by rGO/NF (1200 mW m ^-2 and 680 mA m ^-2 ) were 220-fold and 540-fold higher compared to bare NF (5.50 mW m ^-2 and 1.26 mA m ^-2 ), respectively. Electrochemical impedance spectroscopy results show that rGO/NF suppresses charge transfer resistance to CH ₃ OH oxidation by 40-fold compared to the control. This improved performance is due to the ability of rGO coatings to decrease the wetting contact angle (improve the hydrophilicity) of NF from 128 ⁰ to 0 ⁰ . A preliminary cost analysis was carried out to assess the viability of rGO/NF electrodes via vitamin-C-enabled graphene oxide chemistry for CH ₃ OH-MFCs applications.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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