Search results for "Titanium dioxide"

Gene toxicity studies on titanium dioxide and zinc oxide nanomaterials used for UV-protection in cosmetic formulations

2010

Titanium dioxide and zinc oxide nanomaterials, used as UV protecting agents in sunscreens, were investigated for their potential genotoxicity in in vitro and in vivo test systems. Since standard OECD test methods are designed for soluble materials and genotoxicity testing for nanomaterials is still under revision, a battery of standard tests was used, covering different endpoints. Additionally, a procedure to disperse the nanomaterials in the test media and careful characterization of the dispersed test item was added to the testing methods. No genotoxicity was observed in vitro (Ames' Salmonella gene mutation test and V79 micronucleus chromosome mutation test) or in vivo (mouse bone marrow…

Effects of titanium dioxide pigments on mouse peritoneal macrophages in vivo.

1982

Blue light mediated C–H arylation of heteroarenes using TiO2as an immobilized photocatalyst in a continuous-flow microreactor

2017

Titanium dioxide was applied as an immobilized photocatalyst in a microstructured falling film reactor for the continuous-flow C-H arylation of heteroarenes with aryldiazonium salts as the starting material. Detailed investigations of the catalyst and a successful long-term run proved its excellent usability for this process. Very good yields up to 99% were achieved with broad substrate scope and were compared with batch synthesis. The transfer to the continuous-flow mode revealed an impressive boost in reactor performance solely resulting from the improved irradiation and contact of the catalyst, substrate and light.

Photocatalytic H2 production over inverse opal TiO2 catalysts

2019

Abstract The influence of BiVO4 and CuO on the chemico-physical properties of TiO2-based systems is reported. The performances of these systems were investigated in the photocatalytic H2 production both under UV and solar light irradiation. The characterization data pointed out that the obtained TiO2 samples have highly porous inverse opal structures with interconnected macropores. Inverse opal TiO2 exhibited higher activity in the H2 production than the commercial TiO2 due to the peculiar porosity that allows photons to enter inside the photocatalyst. A further improvement in terms of photoactivity was verified by addition of increasing amounts of BiVO4. On the contrary a small CuO content…

Influence of laser–target interaction regime on composition and properties of surface layers grown by laser treatment of Ti plates

2009

Surface laser treatment of commercially pure titanium plates was performed in air using two different Nd : YAG sources delivering pulses of 5 and 35 ns. The laser fluence conditions were set to obtain with each source either yellow or blue surface layers. Nuclear reaction analysis (NRA) was used to quantify the amount of light elements in the formed layers. Titanium oxinitrides, containing different amounts of oxygen and nitrogen, were mainly found, except in the case of long pulses and high laser fluence, which led to the growth of titanium dioxide. The structure of the layers was studied by x-ray diffraction and Raman spectroscopy. In addition, reflectance spectra showed the transition fr…

Luminescence of X-ray induced radiation defects in modified lithium orthosilicate pebbles with additions of titanium dioxide

2017

The authors greatly acknowledge the technical and experimental support of O. Leys, M. H. H. Kolb, and R. Knitter (Karlsruhe Institute of Technology, Germany). The work is performed in the frames of the University of Latvia financed project No. Y9-B044-ZF-N-300, “Nano, Quantum Technologies, and Innovative Materials for Economics”.

Hybrid organic-inorganic light emitting diodes: effect of the metal oxide

2010

Hybrid organic-inorganic light emitting diodes (HyLEDs), employing metal oxides as the electron injecting contacts, are interesting as an alternative to OLEDs. Until recently, the metal oxide of choice was either titanium dioxide or zinc oxide. In this work two wide bandgap metal oxides, HfO2 and MgO, are employed as electron injecting layer in HyLEDs. It is demonstrated that both the current density and the luminance values obtained are directly related to the barriers for electron injection (from the ITO to the metal oxide) and for hole transfer to the same metal oxide, outlining a new design rule for the optimization of HyLEDs. Record device efficacies (3.3 cd/A, >10000 cd/m2) using the …

TiO2/ORMOSIL Thin Films Doped with Phthalocyanine Dyes:  New Photocatalytic Devices Activated by Solar Light

2008

WOS: 000253222200065

Growth and characterization of AP-MOCVD iron doped titanium dioxide thin films

1999

Abstract Atmospheric pressure metal organic chemical vapor deposition (AP-MOCVD) was used to prepare iron doped titanium dioxide thin films. Thin films, between 40 and 150 nm thick, were deposited on Si, SiO 2 and Al 2 O 3 substrates using titanium tetra isopropoxide and ferrocene as metal organic precursors. TiO 2 iron doping was achieved in the range of 1–4 at.%. The film morphology and thickness, polycrystalline texture and doping content were studied using respectively scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The influence of growth temperature, deposition time, substrate type and dopant partial pressure were studied. Electr…

Mesoporous ZnFe2O4@TiO2 Nanofibers Prepared by Electrospinning Coupled to PECVD as Highly Performing Photocatalytic Materials

2017

International audience; Zinc ferrite @ titanium dioxide (ZnFe2O4@TiO2) composite nanofibers were elaborated by combining the two different techniques: electrospinning and plasma-enhanced chemical vapor deposition (PECVD). The nanofiber compositions were controlled using different ratios of zinc to iron. Their structural, morphological, and optical properties were analyzed by scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, BET surface area, Raman spectroscopy, and UV–visible spectrophotometry. The photocatalytic activity has been investigated by the degradation of methylene blue under visible light. The results indicate that the combination of spinel st…