Electrochemical characteristics of Shewanella loihica on carbon nanotubes-modified graphite surfaces

Xiaoming Zhang, Monica Epifanio, Enrico Marsili

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

High specific surface and electrocatalytic activity of the electrode surface favour extracellular electron transfer from electrochemically active biofilms to polarized electrodes. We coated layer-by-layer carbon nanotubes (CNTs) on graphite electrodes through electrophoretic deposition, thus increasing the electrocatalytic activity. After determining the optimal number of CNT layers through electrochemical methods, we grew Shewanella loihica PV-4 biofilms on the CNT-coated electrodes to quantify the increase in extracellular electron transfer rate compared with unmodified electrodes. Current density on CNT-modified electrodes was 1.7 times higher than that observed on unmodified electrodes after 48 h from inoculation. Rapid microbial cells attachment on CNT-coated electrodes, as determined from scanning electronic microscopy, explained the rapid increase of the current. Also, the CNT reduced the charge transfer resistance of the graphite electrodes, as measured by Electrochemical Impedance Spectroscopy. However, the electrocatalytic activity of the CNT-coated electrode decreased as the biofilm grew thicker and covered the CNT-coating. These result confirmed that surface-modified electrodes improve the electron transfer rate in thin biofilms (<5 μm), but are not feasible for power production in microbial fuel cells, where the biofilm thickness is much higher.

Original languageEnglish
Pages (from-to)252-258
Number of pages7
JournalElectrochimica Acta
Volume102
DOIs
Publication statusPublished - 2013
Externally publishedYes

Keywords

  • Carbon nanotubes
  • Electroactive biofilm
  • Electrophoretic deposition
  • PV-4
  • Shewanella loihica

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry

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