Search

The development of highly efficient photocatalyst under visible light still a challenge. Herein we present band gap modification of NH 2 -MIL-125 by encirclement with suitable semiconductor that possesses a narrow band gap Ag 3 PO 4 nanoparticles (NPs). The band gap of NH 2 -MIL-125 was decreased from 2.51 to 2.39 eV, making them potential candidates for photocatalytic applications. Our prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). TEM characterizations indicated that NH 2 -MIL-125 MOFs are coated with Ag 3 PO 4 NPs. The photocatalytic activity (PCA) was evaluated in the liquid-solid phase, by monitoring the degradation of an organic dye (methylene blue (MB) and rhodamine-B (RhB)) under visible-light irradiation. Furthermore, the Ag 3 PO 4 @NH 2 -MIL-125 nanocomposites shown themselves to be the most active with the reaction rate being 39 and 35 times higher than the well known Degussa P25 TiO 2 toward photocatalytic degradation of MB and RhB. [ABSTRACT FROM AUTHOR]

Abstract: A series of TiO2–SiO2 mixtures – having the following stoichiometry Ti1−x Si x O2, with x =0, 0.1, 0.3 and 0.5 atoms per formula unit – were prepared by using precursor oxides and fired at three temperatures (900, 1000 and 1200°C). The modifications in the structure and, consequently, on the photocatalytic activity, induced by the addition of SiO2 into the TiO2 powder, were thoroughly investigated by using various analytical techniques: X-ray powder diffraction, electron microscopy (FE-SEM and TEM), XPS, FT-IR, DRS and BET analysis. The results underlined as essentially no solid solution occurs between the two crystalline end-members. Nevertheless, silica addition caused a retarding effect on anatase-to-rutile phase transformation and on the crystallite growth. The photocatalytic activity of the powders was assessed in gas phase and the results were explained by taking into account the anatase and rutile relative amounts in the samples, their crystallite size, the surface hydroxyl groups adsorbed on the photocatalysts and the surface area of the mixtures. [Copyright &y& Elsevier]

This article describes the synthesis of tungsten doped (W–TiO 2) nanoparticles and their incorporation into a coating to improve the air quality inside buildings. W–TiO 2 was prepared using a sol-gel synthesis route incorporating 1%, 2.5% and 3% tungsten in TiO 2. Coatings containing the nanoparticles were produced using a water/alcohol liquid phase containing a polyurethane binder and applied to the surface of medium density fibreboard (MDF). Photocatalytic activity of unbound nanoparticles was studied using methylene blue degradation to evaluate liquid/solid interface reactions and NO x degradation to study gas/solid interfacial reactions. The coatings containing the nanoparticles were applied onto the surface of MDF and evaluated using Ink Intelligent indicator dyes. In the tests photocatalytic activity under visible light of all W–TiO 2 concentrations exhibited a higher activity compared to the commercially available Degussa P25. This paper has demonstrated for the first time that polyurethane W–TiO 2 coatings can be effectively applied to MDF and exhibit activity in visible light. • Sol gel synthesis of W–TiO 2 nanoparticles doped with 1%, 2.5% and 3% tungsten. 81. • Evaluation of W–TiO 2 in liquid phase using methylene blue and gas phase using NOx. 85. • Enhanced photocatalytic performance of W–TiO 2 in the visible light spectrum. 79. • Development of polyurethane-based coating for medium density fiber board. 83. • Evaluation of polyurethane W–TiO 2 coating using ink intelligent dyes. 72. [ABSTRACT FROM AUTHOR]

Abstract: Anatase-structured TiO2 films were deposited on a commercial fluorinated polymer (FEP) with a treated surface, by means of a sol–gel dip-coating technique. Two different curing temperatures were investigated and the film microstructures were characterized by X-ray diffraction, atomic force microscopy and scanning electron microscopy analyses. The prepared samples presented very high performances in terms of photocatalytic activities, analyzed by the degradation of an organic dye in a liquid medium, and of bactericidal activities, tested on Staphylococcus aureus (S. aureus, a Gram positive bacterium) and Escherichia coli (E. coli, a Gram negative bacterium). [Copyright &y& Elsevier]