Carbon quantum dots shuttle electrons to the anode of a microbial fuel cell

Abstract

Electrodes based on graphite, graphene, and carbon nanomaterials have been used in the anode chamber of microbial fuel cells (MFCs). Carbon quantum dots (C-dots) are a class of versatile nanomaterials hitherto not reported in MFCs. C-dots previously synthesized from coconut husk were reported to possess hydroxyl and carboxyl functional groups on their surface. The presence of these functional groups on a carbon matrix conferred on the C-dots the ability to conduct and transfer electrons. Formation of silver nanoparticles from silver nitrate upon addition of C-dots confirmed their reducing ability. DREAM assay using a mixed microbial culture containing C-dots showed a 172% increase in electron transfer activity and thus confirmed the involvement of C-dots in supplementing redox activity of a microbial culture. Addition of C-dots as a suspension in the anode chamber of an MFC resulted in a 22.5% enhancement in maximum power density. C-dots showed better performance as electron shuttles than methylene blue, a conventional electron shuttle used in MFCs.

Enhancing Extracellular Electron Transfer of Geobacter sulfurreducens in Bioelectrochemical Systems Using N-Doped Fe3O4@Carbon Dots

“…The C-MEC pathway could represent a transfer from IET to DET to achieve higher methane production. The oxidation peak at 0.1 V was assigned as an outer-membrane electroactive substance for carrying extracellular electrons, and the enhanced current of GS-CD-MEC could be thought of as efficient utilization of electrons for methanogenesis via shuttles between the cathode and the microorganisms. , Furthermore, to better understand the energy transfer pathway and analyze the interfacial consistency on the bioelectrode surface, an equivalent circuit was applied to fit the EIS spectra (Figure b,c). With the equivalent circuit employed, the value of the components was determined.…”

Carbon and graphene quantum dots in fuel cell application: An overview

“…Coconut husk obtained from the local market was washed twice and dried before use in Vishwanathan et al 153 study for the synthesis of the CQD. CQD have been synthesized by hydrothermal cocoa husk in one step.…”

Sustainable Syntheses and Sources of Nanomaterials for Microbial Fuel/Electrolysis Cell Applications: An Overview of Recent Progress

“…The incorporation of carbon nanotubes has found the increase in the power density to be in the order of 6 times, i.e., 2470 mW•m −2 when compared to the 386 mW•m −2 of control cells. Quantum carbon dots have also been found to enhance MFC performance [149]. The improved performance in power density was 22.5% with that of the carbon quantum dots.…”