Titanium Dioxide Nanomaterials: Synthesis, Properties, Modifications, and Applications

Titanium dioxide (TiO2 ) nanocrystals are prepared by a hydrolysis process of tetrabutyl titanate. Nanocrystal samples with various sizes of 6.8-27.9 nm are obtained after annealing from 100 to 650 °C. The crystal structures and the average particle sizes are examined using x-ray diffraction. Raman scattering was employed to investigate the evolution of the anatase phase in the nanocrystals during annealing. Phonon confinement and non-stoichiometry effects are responsible for the blueshift and broadening of the lowest-frequency Eg Raman mode. The influence of interfacial vibrations on the Raman linewidth is also discussed.

https://iopscience.iop.org/article/10.1088/0022-3727/33/8/305/pdf

Raman scattering study on anatase TiO2 nanocrystals

Mesoporous Au/TiO2 nanocomposites with Au nanoparticles homogeneously embedded within crystalline TiO2 framework were synthesized using a simple one-pot assembly approach and exhibit significantly enhanced photocatalytic activity.

Mesoporous Au/TiO2 nanocomposites with enhanced photocatalytic activity.

Surface hybridization of TiO2 with graphite-like carbon layers of a few molecular layers thickness yields efficient photocatalysts. Photoelectrochemical measurements confirm an electronic interaction between TiO2 and the graphite-like carbon. A TiO2 photocatalyst with a carbon shell of three molecular layers thickness (∼1 nm) shows the highest photocatalytic activity which is about two times higher than that of Degussa P25 TiO2 under UV light irradiation. The mechanism of the enhanced photocatalytic activity under UV irradiation is based on the high migration efficiency of photoinduced electrons at the graphite-like carbon/TiO2 interface, which is due to the electronic interaction between both materials. In addition, a high activity under visible light irradiation is observed after graphite-like carbon hybridization. TiO2's response is extended into the visible range of the solar spectrum due to the electronic coupling of π states of the graphite-like carbon and conduction band states of TiO2.

Efficient TiO2 Photocatalysts from Surface Hybridization of TiO2 Particles with Graphite-like Carbon

Size effects in the Raman spectra of TiO2 nanoparticles

Calibration curves of the Raman spectrum of nanophase TiO2 to the material’s oxygen stoichiometry are presented. The thermogravimetric analysis studies used to determine the oxygen‐titanium ratio are also discussed.

R. W. Siegel

Papers

Calibration of the Raman spectrum to the oxygen stoichiometry of nanophase TiO2