Electrochemical Enhancement of Photocatalytic Disinfection on Aligned TiO2 and Nitrogen Doped TiO2 Nanotubes

Cristina Pablos, Javier Marugán, Rafael van Grieken, PSM Dunlop, Jeremy Hamilton, Dionysios Dionysiou, JA Byrne

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

TiO2 photocatalysis is considered as an alternative to conventional disinfection processesfor the inactivation of waterborne microorganisms. The efficiency of photocatalysis is limitedby charge carrier recombination rates. When the photocatalyst is immobilized on an electricallyconducting support, one may assist charge separation by the application of an external electrical bias. The aim of this work was to study electrochemically assisted photocatalysis with nitrogen doped titania photoanodes under visible and UV-visible irradiation for the inactivation of Escherichia coli. Aligned TiO2 nanotubes were synthesized (TiO2-NT) by anodizing Ti foil. Nanoparticulate titania films were made on Ti foil by electrophoretic coating (P25 TiO2). N-doped titania nanotubes and N,F co-doped titania films were also prepared with the aim of extending the active spectrum into the visible. Electrochemically assisted photocatalysis gave higher disinfection efficiency in comparison to photocatalysis (electrode at open circuit) for all materials tested. It is proposed that electrostatic attraction of negatively charged bacteria to the positively biased photoanodes leads to the enhancement observed. The N-doped TiO2 nanotube electrode gave the most efficient electrochemically assisted photocatalytic inactivation of bacteria under UV-Vis irradiation but no inactivation of bacteria was observed under visible only irradiation. The visible light photocurrent was only a fraction (2%) of the UV response.
Original languageEnglish
Number of pages15
JournalMolecules
Volume22
Issue number5
DOIs
Publication statusPublished - 28 Apr 2017

Keywords

  • titania nanotubes
  • nitrogen-doped nanotubes
  • photoelectrocatalysis
  • E. coli
  • visible light

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