A surface science perspective on TiO2 photocatalysis

Vertically aligned ZnO nanotubes were prepared by etching ZnO rod arrays in aqueous solution, which were previously developed by chemical bath deposition method. The morphological, structural, photoluminescence, as well as photocatalytic properties of the ZnO nanotubes were examined with respect to the pH values of chemical bath solution. The morphology of the products was found to be sensitive to the pH values and chemical bath temperatures. The nanotubes synthesized at a low pH value (5.82) exhibited a strong UV emission and a weak defect-related visible emission. The highest photocatalytic efficiency was also observed at pH = 5.82. The possible mechanism for the difference of photocatalytic efficiency was discussed.

Formation and photocatalytic application of ZnO nanotubes using aqueous solution.

Self-cleaning coatings, with benefits to environment, energy and labor saving, have attracted great attention due to their potential application in many aspects of human's daily life. In this perspective article, the recent efforts to understand and improve photo-induced hydrophilicity and self-cleaning properties of TiO2 are reviewed. Particular attention is paid to the fundamental aspects and mechanism of the photo-induced hydrophilicity effect. The challenges that need to be addressed over the coming years to improve the efficiency and extend the application are also presented.

Photo-induced hydrophilicity and self-cleaning: models and reality

Photodegradation of azo dye Congo Red from aqueous solution by the WO3–TiO2/activated carbon (AC) photocatalyst under the UV irradiation

Mesostructrured CeO 2 –TiO 2 nanoparticles with different CeO 2 contents have been successfully synthesized using ionic liquid (1-hexadecane-3-methylimidazolium bromide, C 16 MIM + Br − ) as a template by a hydrothermal method. The prepared materials were characterized by means of X-ray diffraction (XRD), nitrogen adsorption–desorption, transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectra analysis. The obtained CeO 2 –TiO 2 materials exhibit large specific surface area and uniform pore sizes. Introduction of CeO 2 species can effectively extend the spectral response from UV to visible area and enhance the surface hydroxyl groups of the mesoporous TiO 2 . The CeO 2 –TiO 2 nanocomposites show high photocatalytic activity in the degradation of the p -chlorophenol aqueous solution under the UV or visible irradiation.

Ionic liquid-templated synthesis of mesoporous CeO2–TiO2 nanoparticles and their enhanced photocatalytic activities under UV or visible light

Photocatalytic properties of SnO2/TiO2 multilayers

The crystallization of amorphous indium tin oxide (ITO) films was achieved by rf (13.56MHz) plasma treatment. Although the films were crystallized after 2min, the sample temperature was lower than 90°C without compulsory cooling even after 10min of treatment and polyethylene terephthalate (PET) substrates had no damage. Plasma-crystallized sputtered ITO films have a bixbite structure and the resistivity reached to 1.6×10−4Ω∙cm. ITO thin films have almost the same resistivity in both cases of PET and glass substrates used and plasma-treated PET ITO films have a bit higher resistivity than that of glass ITO films, while mass spectroscopy measurements indicated that ITO films deposited on PET substrates are expected to include no apparent gas species ejected from PET substrate. It was found that the plasma gas pressure is the key parameter for the effective crystallization and the appropriate gas pressure depends on the plasma gas species.

M. Suzuki

Papers

Photocatalytic properties of SnO2/TiO2 multilayers

Room temperature crystallization of indium tin oxide films on glass and polyethylene terephthalate substrates using rf plasma

Room temperature crystallization by RF plasma

Characterization of sputtered triple layer photoactive coating with a glass-like appearance