16 documents found, page 1 of 2
Immobilisation of ZnO nanoparticles on carbon and on glass fibres for visible l...
Ferreira, Inês V.; Neng, Nuno R.; Monteiro, Olinda C.; Ferreira, Virgínia C.Crystalline zinc oxide (ZnO) nanoparticles (NP) have been used for the evaluation of the effect of manganese doping on the photocatalytic performance towards the degradation of pharmaceutical products and for the preparation of photoactive composite materials based on fibres and ZnO. The presence of manganese effected on the particles size, as obtained by TEM analysis, and the impact on the crystallographic and...
A comparative study on emergent pollutants photo-assisted degradation using rut...
Barrocas, Beatriz; Conceição Oliveira, M.; Nogueira, Helena I. S.; Fateixa, Sara; Monteiro, Olinda C.Several methods have been used to tailor nanomaterials structure and properties. Sometimes, slight changes in the structure outcomes expressive improvements in the optical and photocatalytic properties of semiconductor nanoparticles. In this context, the influence of the metal doping and the morphology on a catalyst performance was studied in this work. Here, ruthenium doped titanate nanotubes (RuTNT) were synt...
When gold stops glittering: corrosion mechanisms of René Lalique's Art Nouveau ...
Tissot, Isabel; Correia, Jorge; Monteiro, Olinda C.; Barreiros, M. Alexandra; Guerra, M. F.ABSTRACT: Art Nouveau jewellery created by René Lalique is presently corroded. To identify the corrosion processes, Au-Ag-Cu alloys with compositions comparable to those used in the René Lalique’s jewellery were fabricated to be exposed to sulphide-containing environments. Using SEM-EDS, XRD, UV-Vis spectroscopy and ellipsometry, it was for the first time demon-strated that at the surface of tarnished Au alloys...
When gold stops glittering: corrosion mechanisms of René Lalique's Art Nouveau ...
Tissot, Isabel; Correia, Jorge; Monteiro, Olinda C.; Barreiros, M. Alexandra; Guerra, M. F.ABSTRACT: Art Nouveau jewellery created by René Lalique is presently corroded. To identify the corrosion processes, Au-Ag-Cu alloys with compositions comparable to those used in the René Lalique’s jewellery were fabricated to be exposed to sulphide-containing environments. Using SEM-EDS, XRD, UV-Vis spectroscopy and ellipsometry, it was for the first time demon-strated that at the surface of tarnished Au alloys...
Ruthenium-Modified Titanate Nanowires for the Photocatalytic Oxidative Removal ...
Barrocas, Beatriz T.; Oliveira, M. Conceição; Nogueira, Helena I. S.; Fateixa, Sara; Monteiro, Olinda C.Titanate elongated nanomaterials have been studied as promising catalysts for photoassisted oxidation processes, and various methods have been used to tailor their properties. In this context, the synthesis and photocatalytic evaluation of novel ruthenium-modified titanate nanowires is described. In this work, pristine (TNW) and modified nanowires (RuTNW) were obtained through the hydrothermal treatment of an a...
Electron microscopy and spectroscopy studies of modified titanate nanostructures
Sathyanath, Sharath Kumar Manjeshwar; Barrocas, Beatriz; Monteiro, Olinda C.; Rolo, Anabela G.; Anumol, E. A.; Deepak, Francis LeonardTitanate nanotubes (TNTs), such as that of Na2Ti3O7, are investigated as alternatives to TiO2 for photocatalysis, as they combine the properties of TiO2 nanoparticles with the properties of layered titanates such as cation exchangeability and open mesoporous morphology with higher specific surface area. Recently spectroscopic investigations using XPS and Raman spectroscopy on cobalt modified TNT samples showed ...
Biotechnologically obtained nanocomposites: A practical application for photode...
da Costa, Joao Pinto; Girao, Ana V.; Monteiro, Olinda C.; Trindade, Tito; Costa, Maria C.This research was undertaken to determine the potential of biologically obtained ZnS-TiO2 nanocomposites to be used as catalysts in the photodegradation of organic pollutants, namely, Safranin-T. The photocatalysts were prepared by modifying the surface of commercial TiO2 particles with naturally produced ZnS, using sulfide species produced by sulfate-reducing bacteria and metal contaminated wastewaters. Compar...
A new chemical route to synthesise TM-doped (TM = Co, Fe) TiO2 nanoparticles
Nunes, Manuel R.; Monteiro, Olinda C.; Castro, Ana L.; Vasconcelos, Duarte A.; Silvestre, António JorgeSince the discovery of ferromagnetism well above room temperature in the Co-doped TiO2 system, diluted magnetic semiconductors based on TiO2 doped with transition metals have generated great interest because of their potential use in the development of spintronic devices. The purpose of this paper is to report on a new and swift chemical route to synthesise highly stable anatase single-phase Co- and Fe-doped Ti...
Adsorption and catalytic properties of SiO2/Bi2S3 nanocomposites on the methyle...
Albuquerque, Rita; Neves, Márcia C.; Mendonça, Maria H.; Trindade, Tito; Monteiro, Olinda C.The decolorization of aqueous solutionsmethylene blue (C.I. Basic Blue 9), due to the presence of nanocrystalline Bi2S3, supported on SiO2 submicron particles,was investigated here. For this decolorization process, two distinct characteristics, though related, associated to the role of SiO2/Bi2S3 were identified: (i) high methylene blue adsorption capability and (ii) photocatalytic activity to methylene blue ph...
From single-molecule precursors to coupled Ag2S/TiO2 nanocomposites
Neves, Márcia C.; Monteiro, Olinda C.; Hempelmann, Rolf; Silva, Artur M. S.; Trindade, TitoA single-source approach using mild temperatures was applied to prepare morphological well-defined and coupled TiO2/metal–sulfide nanocomposites. Metal N-alkyldithiocarbamates were used as the precursors to the metal–sulfide nanophases and, in particular, Ag2S nanostructures were investigated in more detail. These were observed as nanoislands at the surface of TiO2 (anatase) particles, which were used as substr...