Formation of hydroxyl radicals and kinetic study of 2-chlorophenol photocatalytic oxidation using C-doped TiO2, N-doped TiO2, and C,N Co-doped TiO2 under visible light

Jirapat Ananpattarachai, Supapan Seraphin, Puangrat Kajitvichyanukul

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Abstract

This work reports on synthesis, characterization, adsorption ability, formation rate of hydroxyl radicals (OH), photocatalytic oxidation kinetics, and mineralization ability of C-doped titanium dioxide (TiO2), N-doped TiO2, and C,N co-doped TiO2 prepared by the sol–gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV–visible spectroscopy were used to analyze the titania. The rate of formation of OH for each type of titania was determined, and the OH-index was calculated. The kinetics of as-synthesized TiO2 catalysts in photocatalytic oxidation of 2-chlorophenol (2-CP) under visible light irradiation were evaluated. Results revealed that nitrogen was incorporated into the lattice of titania with the structure of O-Ti-N linkages in N-doped TiO2 and C,N co-doped TiO2. Carbon was joined to the Ti-O-C bond in the C-doped TiO2 and C,N co-doped TiO2. The 2-CP adsorption ability of C,N co-doped TiO2 and C-doped TiO2 originated from a layer composed of a complex carbonaceous mixture at the surface of TiO2. C,N co-doped TiO2 had highest formation rate of OH and photocatalytic activity due to a synergistic effect of carbon and nitrogen co-doping. The order of photocatalytic activity per unit surface area was the same as that of the formation rate of OH unit surface area in the following order: C,N co-doped TiO2 > C-doped TiO2 > N-doped TiO2 > undoped TiO2.

Original languageEnglish (US)
Pages (from-to)3884-3896
Number of pages13
JournalEnvironmental Science and Pollution Research
Volume23
Issue number4
DOIs
Publication statusPublished - Feb 1 2016

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Keywords

  • Hydroxyl radical
  • Oxidation
  • Phenol
  • Photocatalyst
  • TiO
  • Visible light

ASJC Scopus subject areas

  • Environmental Chemistry
  • Health, Toxicology and Mutagenesis
  • Pollution

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