Chemistry of and on TiO2-anatase surfaces by DFT calculations: a partial review
250
Citation
51
Reference
10
Related Paper
Citation Trend
Keywords:
Reactivity
The surface properties of TiO2 anatase are of great importance in chemical technology because this material is frequently used as a support for oxide catalysts. In the framework of an extensive study of the system V2O5/TiO2 anatase, the vibrational properties of single crystal anatase (001) and (100) have been examined by means of HREELS. Both of these surfaces are believed to provide a good lattice match with V2O5(001). Single crystal anatase samples were obtained by orienting and sawing natural minerals. The resulting samples were yellowish transparent and gave rise to a LEED image after adequate UHV cleaning. Despite the insulating character of TiO2 anatase, HREELS could be performed without charging problems, due to the natural contamination. Energy loss spectra were recorded in the range −140 to 40 meV, with an instrument resolution of about 3 meV, and displayed surface vibrational modes.
Crystal (programming language)
Cite
Citations (11)
The crystal structure of three efficient Ru-sensitizers of TiO2 anatase nanopowders are discussed in terms of formation of two-dimensional molecular packings on the anatase surfaces. The surface areas of sensitizer molecules on the flat semiconductor surfaces are calculated. The symmetry of the (001) and (101) surface of naturally grown TiO2 anatase has been investigated using low-energy electron diffraction (LEED) technique. The first results on the orientation of sensitizer molecules on the mostly exposed surface (101) of anatase single crystal are obtained from HRTEM data. The amount of sensitizer molecules on the mostly exposed faces of anatase nanocrystals in thin colloidal TiO2 anatase films could be estimated using crystal structure data on both sensitizers structures and anatase surface.
Crystal (programming language)
Cite
Citations (0)
Reactivity
Cite
Citations (250)
Hydroxyapatite (HAp) was crystallized on anatase titanium dioxide (TiO 2 ) photocatalytic crystals or their thin films using of a pseudo‐body solution method, and electrochemical properties of the HAp‐adhered anatase TiO 2 photocatalytic surfaces were discussed. Decomposition rates of methylene blue were faster for the HAp‐adhered anatase TiO 2 photocatalysts, although specific surface areas were smaller than those for the commercial anatase TiO 2 ones. Surface potential dispersions on the HAp‐adhered anatase TiO 2 thin films before and after an ultraviolet light irradiation were measured by an atomic force microscopy. Changes in the color of leucocrystalviolet mixed in the HAp‐adhered anatase TiO 2 photocatalysts or the commercial anatase TiO 2 ones with experimental durations were compared. Movements of electrons from the anatase TiO 2 photocatalytic surfaces to the HAp, crystals and oxidizing reactions on the HAp‐adhered anatase TiO 2 photocatalytic surfaces in the dark were discussed on the basis of these experimental results.
Titanium Dioxide
Methylene blue
Oxidizing agent
Cite
Citations (13)
Rutile
Cite
Citations (50)
Reactivity
Cite
Citations (41)
Chemisorption
Cite
Citations (2)
In this study, CuO loaded on anatase TiO2 catalysts (CuO/anatase) with oxygen vacancies was synthesized via reduction treatments by NaHB4 and H2 (CuO/anatase-B, CuO/anatase-H), respectively. The characterizations suggest that different reduction treatments bring different concentration of oxygen vacancies in the CuO/anatase catalysts, which finally affect the CO catalytic performance. The CuO/anatase-B and CuO/anatase-H exhibit CO conversion of 90% at 182 and 198 °C, respectively, which is lower than what occurred for CuO/anatase (300 °C). The XRD, Raman, and EPR results show that the amount of the oxygen vacancies of the CuO/anatase-H is the largest, indicating a stronger reduction effect of H2 than NaHB4 on the anatase surface. The in situ DRIFTS results exhibit that the Cu sites are the adsorption sites of CO, and the oxygen vacancies on the anatase can active the O2 molecules into reactive oxygen species. According to the in situ DRIFTS results, it can be concluded that in the CO oxidation reaction, only the CuO/anatase-H catalyst can be carried out by the Mvk mechanism, which greatly improves its catalytic efficiency. This study explained the reaction mechanisms of CO oxidation on various anatase surfaces, which offers detailed insights into how to prepare suitable catalysts for low-temperature oxidation reactions.
Cite
Citations (0)
Rutile
Cite
Citations (22)
TiO2 is as promising photocatalyst for environmental degradation of organic compounds and solar energy conversion. Commercial titania is a mixture of rutile and anatase phases, and, for as of yet unknown reasons, anatase is the photocatalytically more active form. In contrast to rutile, atomic-scale information on well-characterized anatase surfaces and their chemical properties was virtually absent at the beginning of this project. We have performed surface science investigations of anatase with the goal to understand, and ultimately control, the surface chemistry underlying its diverse applications. We have of (1) characterized all main crystallographic surface orientations of anatase, namely the (101), (100), (001), and (103) surfaces (2) have investigated the influence of surface imperfections such as defects and steps; (3) have investigated the influence of dopants on epitaxial (001) anatase films; and (3) have investigated the chemical and adsorption and reaction processes of simple molecules (water and methanol) on anatase surfaces. The experiments were performed in collaboration with Pacific Northwest National Laboratory (PNNL) using a variety of complementary surface science techniques. They have lead to a thorough characterization of this model system and have provided a more complete understanding of TiO2, which could possibly lead to improved efficiency in of photocatalytic applications.
Rutile
Characterization
Cite
Citations (0)