title: Graphene TiO2 nanocomposites with high photocatalytic activity for the degradation of sodium pentachlorophenol.
abstract: A series of graphene-TiO2 photocatalysts was synthesized by doping TiO2 with graphene oxide via hydrothermal treatment. The photocatalytic capability of the catalysts under ultraviolet irradiation was evaluated in terms of sodium pentachlorophenol (PCP-Na) decomposition and mineralization. The structural and physicochemical properties of these nanocomposites were characterized by X-ray diffraction, N2 adsorption-desorption, transmission electron microscopy, scanning electron microscopy, Ultraviolet-visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance spectra, and Fourier-transform infrared spectroscopy. The graphene-TiO2 nanocomposites exhibited higher photocatalytic efficiency than commercial P25 for the degradation of PCP-Na, and 63.4% to 82.9% of the total organic carbon was fully mineralized. The improved photocatalytic activity may be attributed to the accelerated interfacial electron-transfer process and the significantly prolonged lifetime of electron-hole pairs imparted by graphene sheets in the nanocomposites. However, excessive graphene and the inhomogeneous aggregation of TiO2 nanoparticles may decrease photodegradation efficiency.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: zhang_yx@hnu.edu.cn.
authors.forename: Yaxin
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Zeyu
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Tan
authors.initials: T
authors.lastname: Chen
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: htwang@tsinghua.edu.cn.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Lu
mesh_terms: D002384:Catalysis; D018360:Crystallography, X-Ray; D004579:Electron Transport; D006108:Graphite; D008854:Microscopy, Electron; D053761:Nanocomposites; D010416:Pentachlorophenol / Q000737:chemistry*; D055668:Photochemical Processes; D013057:Spectrum Analysis / Q000379:methods; D014025:Titanium / Q000737:chemistry*
chemical_list: C009495:titanium dioxide; D006108:Graphite; D014025:Titanium; D010416:Pentachlorophenol
keywords: Degradation; Graphene; PCP-Na; Photocatalysis; TiO(2)