The fabrication and characterization of novel carbon doped TiO₂nanotubes, nanowires and nanorods with high visible light photocatalytic activity

Abstract

Novel carbon doped TiO(2) nanotubes, nanowires and nanorods were fabricated by utilizing the nanoconfinement of hollow titanate nanotubes (TNTs). The fabrication process included adsorption of ethanol molecules in the inner space of TNTs and thermal treatment of the complex in inert N(2) atmosphere. The structural morphology of carbon doped TiO(2) nanostructures can be tuned using the calcination temperature. X-ray diffraction, Raman and Brunauer-Emmett-Teller studies proved that the doped carbon promoted the crystallization and phase transition by acting as nucleation seeds. X-ray photoelectron spectroscopy (XPS) showed that O-Ti-C and Ti-O-C bonds were formed in the nanostructures. Additional electronic states from the XPS valence band due to carbon doping were observed. This evidence indicated the electronic origin of the band gap narrowing and visible light absorption. The differences in chemical and electronic states between the surface and bulk of as-prepared samples confirmed that carbon was doped into the lattice of TiO(2) nanostructure through an inner doping process. The as-prepared catalysts exhibited enhanced photocatalytic activity for degradation of toluene in gas phase under both visible and simulated solar light irradiation compared with that of commercial Degussa P25. This novel fabrication approach can valuably contribute to designing nanostructured photocatalytic materials and modifying various nanotube materials.

Synthesis of highly efficient C-doped TiO2 photocatalyst and its photo-generated charge-transfer properties

“…Thus, It can form C-O bond via substitution carbon for titanium site or as interstitial carbon and can form Ti-C bond via substitution of carbon for oxygen site in TiO 2 lattice [5][6][7][8][9][10][11][12][13], resulting in the band gap narrowing of TiO 2 or the formation of localized mid-gap state [14,15]. Kang et al successfully synthesized a visible sensitive carbon doped titanium oxide powder by grinding TiO 2 with ethanol and heating treatment at different temperatures in air.…”

Marked enhancement of photocatalytic activity and photochemical stability of N–doped TiO2 nanocrystals by Fe3+/Fe2+ surface modification

“…However, TiO 2 only becomes active under irradiation with ultraviolet (UV) light [1][2][3]. Thus, many efforts have been devoted recently to improve the optical response of TiO 2 in the visible light region [4][5][6][7][8][9][10][11][12][13][14][15][16].…”

“…Since then, many efforts have been attempted by modification TiO 2 with anionic nonmetals, such as B [5,6], C [7][8][9], N [4,[10][11][12], S [13][14][15], and X (X = F, I) [16,17], so that a greater portion of the solar spectrum or just indoor light may be used to provide visible light photocatalytic capability. However, nonmetal doping intrinsically brings the serious problem of massive charge carrier recombination, which largely limits the photoactivity of nonmetal-doped TiO 2 under visible light illumination [18].…”

Preparation of multiple-doped TiO2 nanotube arrays with nitrogen, carbon and nickel with enhanced visible light photoelectrochemical activity via single-step anodization

“…The peak around 284.8 eV is usually assigned to carbon adsorbed on the surface of the photocatalyst as a contaminant, namely CeC bonds, which cannot be eliminated. The peak at 286.47 eV can be ascribed to the existence of TieCeO bonds, as carbonate species [63]. The peaks observed at binding energies of 287.9 and 288.97 eV, are attributed to C]O and OeC]O bonds, respectively [63e65].…”