Increasing the antioxidant activity of green tea polyphenols in the presence of iron for the reduction of graphene oxide

Akhavan, O ; Sharif University of Technology | 2012

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  1. Type of Document: Article
  2. DOI: 10.1016/j.carbon.2012.02.087
  3. Publisher: 2012
  4. Abstract:
  5. An easy method for green and low-temperature (40 °C) reduction of graphene oxide (GO) by increasing the antioxidant activity of green tea polyphenols (GTPs) in the presence of iron was developed. The reduction level (obtained by X-ray photoelectron spectroscopy) and electrical conductivity (obtained by current-voltage measurement) of the GO sheets reduced by GTPs in the presence of iron were comparable to those of hydrazine-reduced GO and much better than those of the GO reduced by only GTPs (in the absence of iron) at reduction temperatures of 40-80 °C. Raman spectroscopy indicated that application of GTPs in the presence of iron, in contrast to hydrazine, resulted in better recovering of the sp 2-hybridized structure of the sheets. The lasting water dispersion of the polyphenolic-reduced GO sheets in the presence of iron was assigned to π-π adsorption of Fe 2+- polyphenol radicals on surface of the reduced sheets. A mechanism describing the role of iron in the reduction of the GO by epicatechin gallate and epigallocatechin gallate of green tea was also proposed
  6. Keywords:
  7. Antioxidant activities ; Current-voltage measurements ; Electrical conductivity ; Epicatechin gallate ; Epigallocatechin gallate ; Graphene oxides ; Green tea ; Green tea polyphenols ; Low temperatures ; Polyphenols ; Reduction level ; Reduction temperatures ; Water dispersion ; Adsorption ; Electric conductivity ; Hydrazine ; Phenols ; Raman spectroscopy ; X ray photoelectron spectroscopy ; Iron
  8. Source: Carbon ; Volume 50, Issue 8 , 2012 , Pages 3015-3025 ; 00086223 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S0008622312002242