Adverse effects of graphene incorporated in TiO 2 photocatalyst on minuscule animals under solar light irradiation

Akhavan, O ; Sharif University of Technology | 2012

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  1. Type of Document: Article
  2. DOI: 10.1039/c2jm35228a
  3. Publisher: 2012
  4. Abstract:
  5. The adverse effect of graphene-titanium oxide composite films (containing sheet-like surface morphology) on Caenorhabditis elegans nematodes (as a model for minuscule animals) was investigated in a solar light-induced photocatalytic process. X-ray photoelectron spectroscopy demonstrated photocatalytic reduction of the chemically exfoliated graphene oxide sheets included in the TiO 2 film. Furthermore, formation of TiC and Ti-O-C bonds in the composite film (obtained through annealing at 450 °C in air) resulted in a substantial delay in the recombination rate of the photoexcited electron-hole pairs and more efficient photocatalytic processes. The composite film showed a type of concentration-dependent cytotoxic effect on the nematodes under irradiation. The rapid (4 h) photoinactivation of the nematodes by the composite films was assigned to a high generation of reactive oxygen species (ROS) under solar light irradiation (∼25× of the ROS level of a control sample in dark), rather than the strong photoinactivation of Escherichia coli bacteria, which was utilized as the food of the nematodes in a culture medium. The threshold ROS level for inactivation of the nematodes was found ∼19× of the control level which was unreachable using TiO 2. These results warn us of the destruction of minuscule animals of our environment through extensive application of highly efficient graphene-titanium oxide photocatalysts
  6. Keywords:
  7. Adverse effect ; Caenorhabditis elegans ; Concentration-dependent ; Control level ; Control samples ; Culture medium ; Cytotoxic effects ; Escherichia coli bacteria ; Graphene oxides ; Oxide composites ; Photocatalytic process ; Photocatalytic reduction ; Photoexcited electron-hole pairs ; Photoinactivation ; Reactive oxygen species ; Recombination rate ; Sheet-like ; Solar light irradiation ; Substantial delays ; TiO ; Animals ; Cytotoxicity ; Graphene ; Irradiation ; Photocatalysts ; Photoelectrons ; Titanium ; Titanium carbide ; Titanium dioxide ; X ray photoelectron spectroscopy ; Composite films
  8. Source: Journal of Materials Chemistry ; Volume 22, Issue 43 , 2012 , Pages 23260-23266 ; 09599428 (ISSN)
  9. URL: http://pubs.rsc.org/en/Content/ArticleLanding/2012/JM/c2jm35228a#!divAbstract