INVESTIGADORES
FLEXER Victoria
congresos y reuniones científicas
Título:
A novel carbon nanotube modified scaffold creates an efficient biocathode material for improved microbial electrosynthesis
Autor/es:
JOURDIN, L.; VICTORIA FLEXER; CHEN, J.; WALLACE, G.G.; FREGUIA, S.; KELLER, J.
Lugar:
Laussane
Reunión:
Conferencia; 65th Annual Meeting of the International Society of Electrochemistry; 2014
Institución organizadora:
International Society of Electrochemistry
Resumen:
Microbial
electrosynthesis (MES) is a novel strategy for the renewable production of
organic commodities from the microbial reduction of carbon dioxide [1].
Successful optimization of microbial electrosynthesis processes and scale-up to
practical applications requires significant performance improvement while
maintaining low costs. Here we report on a novel biocompatible, highly
conductive three-dimensional cathode synthesized by direct growth of multi-wall
carbon nanotubes (CNT) on reticulated vitreous carbon, NanoWeb-RVC [2], for
the improvement of MES. The CNT surface appears as a fine roughness on the
surface.
NanoWeb-RVC allows for an
enhanced bacterial attachment and biofilm development within its hierarchical
porous structure. Moreover, 1.65 and 2.6 fold higher current density (0.29 mA
cm-2) and acetate bioproduction rate (0.103 mM cm-2 day-1)
normalized by the total surface area within the porous macrostructure were
reached on NanoWeb-RVC versus flat carbon plate control, for the microbial
reduction of carbon dioxide by a mixed culture at ‑0.85 V vs. SHE. To the best
of our knowledge, this is the first study showing better intrinsic efficiency (normalization
by total surface area) for a three-dimensional biocathode versus a flat
electrode. Unmodified reticulated vitreous carbon lacking the nanostructure was
also tested and found to be far less efficient for MES. However, the combination
of the macrostructured RVC with the nanostructured surface modification creates
significant advantages. The high surface area to volume ratio of the
macroporous RVC maximizes the available biofilm area while ensuring effective
mass transfer to and from the biocatalysts. The carbon nanostructure, in turn, enhances
the microbe-electrode interaction and microbial extracellular electron
transfer. When normalized by projected surface area, very high cathodic current
density (3.72 mA cm-2) and acetate production rate (1.325 mM cm-2
day-1) were reached which makes the NanoWeb-RVC an extremely
efficient material from an engineering perspective as well. This current
density and acetate production rate are the highest reported to date for a
cathodic MES.