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Abstract: TiO2 photocatalysts deposited on activated carbon (TiO2/AC) were prepared by dip-hydrothermal method at 180°C using peroxotitanate as a precursor, then calcinated at 300–800°C. The samples were characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy and the nitrogen absorption. Their photocatalytic activity was evaluated by degradation of methyl orange (MO). The results showed that TiO2 particles of anatase type were well deposited on the activated carbon surface. TiO2/AC calcinated at 600°C exhibited the best photocatalytic performance. For the comparison, the same photocatalysis experiment was carried out for two mixtures of commercial TiO2 (Degussa P25) with AC and synthetic TiO2 with AC. It was found that the composite catalyst TiO2/AC was better than the two mixtures. Besides, different from fine powdered TiO2, the granular TiO2/AC photocatalysts could be easily separated from the bulk solution and reused; indeed, its photocatalytic ability was hardly decreased after a five-cycle for MO degradation. The kinetics of the MO degradation fitted well the Langmuir–Hinshelwood model. [Copyright &y& Elsevier]

Abstract: The clarification of the excited states dynamics on TiO2 surface is important subject for the design of the highly active photocatalysts. In the present study, we applied our novel tight-binding quantum chemical molecular dynamics method to the investigation on the photocatalytic oxidation dynamics of acetone by photogenerated radicals on the hydrated anatase TiO2 surface. The elucidated photocatalytic reaction mechanism strongly supports the previous experimental proposal and finally the effectiveness of our new approach for the clarification of the photocatalytic reaction dynamics employing the large simulation model was confirmed. [Copyright &y& Elsevier]

Abstract: The photodegradation of sulforhodamine B on vanadium-doped TiO2–montmorillonite (TiO2–MMT) nanocomposites was investigated under visible light irradiation. V-TiO2–MMT nanocomposites with different amounts of MMT were prepared by a sol–gel process. The microstructure and properties of V-TiO2–MMT were characterized by XRD, TEM, XPS, DRS, nitrogen adsorption isotherms, and FTIR. These analytic results indicated that the different Ti/MMT ratios exerted a great influence on their microstructures and their photocatalytic activities. The average sizes of V-TiO2–MMT were smaller than those of pure TiO2 and V-TiO2. And the layered structure of MMT was completely destroyed in the V-TiO2–MMT with the relatively high ratio of Ti/MMT (240, 120, 80, 60mmol/g), but it retained the partial MMT layered structure and had an enlargement of some basal space of MMT in V-TiO2–MMT with the relatively low ratio of Ti/MMT (30, 24mmol/g). V-TiO2–MMT/120 (120 denotes the ratio of Ti/MMT is 120mmol/g. The names of other catalysts followed the same convention.) and V-TiO2–MMT/30 had relatively higher photocatalytic activity in comparison to the others. Besides, in the preparation process, we selected V-TiO2–MMT/120 using different washing media to examine the effect of washing medium on the photocatalytic activity. The result indicated that it was critical to choose a proper washing medium to obtain an optimal photocatalytic activity. [Copyright &y& Elsevier]

Abstract: Recent progress in ultrafine-grained/nano-grained (UFG/NG) titanium permits a consideration for TiO2 films deposited on nano-grained titanium for antithrombogenic application such as artificial valves and stents. For this paper, the microstructure, interface bonding, surface energy, and blood compatibility features of TiO2 films deposited by direct current magnetron reactive sputtering technology on NG titanium and coarse-grained (CG) titanium were investigated. The results show that the nanocrystallization of titanium substrate has a significant influence on TiO2 films. At the same deposition parameters, the content of rutile phase of TiO2 film was increased from 47% (on the CG titanium substrate) to 72% (on the NG titanium substrate); the adhesion of TiO2 film was improved from 5.8N to 17N; the surface energy was reduced from 6.37dyn/cm to 3.01dyn/cm; the clotting time was improved from 18min to 28min; the platelets accumulation and pseudopodium of adherent platelets on TiO2 film on NG titanium were considerably reduced compared to that on CG titanium. The present results demonstrate the possibility of improving the blood compatibility of TiO2 film through the approach of substrate nanocrystallization. Also it may provide an attractive idea to prepare stents with biological coatings of more outstanding blood compatibility and interface bonding. [ABSTRACT FROM AUTHOR]