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.
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.
Center of Excellence on Environmental Research and Innovation, Faculty of Engineering, Naresuan University, Phitsanulok, 65000, Thailand.
Jirapat
J
Ananpattarachai
Department of Materials Science and Engineering, University of Arizona, Tucson, AZ, 85721, USA.
Supapan
S
Seraphin
Center of Excellence on Environmental Research and Innovation, Faculty of Engineering, Naresuan University, Phitsanulok, 65000, Thailand. puangratk@nu.ac.th.
Puangrat
P
Kajitvichyanukul
D002244:Carbon / Q000737:chemistry; D002384:Catalysis; D002733:Chlorophenols / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D008027:Light; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D009584:Nitrogen / Q000737:chemistry; D010084:Oxidation-Reduction; D055668:Photochemical Processes; D056951:Photoelectron Spectroscopy; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
D002733:Chlorophenols; C009495:titanium dioxide; D017665:Hydroxyl Radical; D002244:Carbon; D014025:Titanium; C030683:2-chlorophenol; D009584:Nitrogen
Hydroxyl radical; Oxidation; Phenol; Photocatalyst; TiO2; Visible light