scholarly journals Characterization of Photoactive Fe-TiO2 Lime Coatings for Building Protection: The Role of Iron Content

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1847 ◽  
Author(s):  
Chrysi Kapridaki ◽  
Nikolaos Xynidis ◽  
Eleftheria Vazgiouraki ◽  
Nikolaos Kallithrakas-Kontos ◽  
Pagona Maravelaki-Kalaitzaki
Keyword(s):  
Tio2 Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Visible Radiation ◽  
Edge Structure ◽  
Doped Tio2 ◽  
X Ray ◽  
Vis Spectroscopy

Iron-doped TiO2 nanoparticles, ranging in Fe concentrations from 0.05 up to 1.00% w/w, were synthesized through a simple sol-gel method. Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Ultraviolet-Visible (UV-Vis) spectroscopy, nitrogen adsorption−desorption isotherms, X-ray photoelectron spectroscopy (XPS), and X-ray absorption near-edge structure spectroscopy (XANES) were used to characterize the synthesized nanoparticles. The characterization of the Fe-doped TiO2 nanoparticles revealed the predominant presence of anatase crystalline form, as well as the incorporation of the Fe3+ ions into the crystal lattice of TiO2. The photocatalytic assessment of the Fe-doped TiO2 nanoparticles indicated that the low iron doping titania (0.05 and 0.10% w/w) have a positive effect on the photocatalytic degradation of Methyl Orange under visible radiation. Moreover, FTIR monitoring of calcium hydroxide pastes enriched with low Fe-doped TiO2 revealed enhancement of carbonation at both early and later stages. Improved photocatalytic performance and increased lime carbonation, observed in lime coatings with low Fe-doped TiO2 admixtures, established them as invaluable contributors to the protection of the built environment.

scholarly journals Application of Reverse Micelle Sol–Gel Synthesis for Bulk Doping and Heteroatoms Surface Enrichment in Mo-Doped TiO2 Nanoparticles

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 937 ◽  
Author(s):  
Roberto Nasi ◽  
Serena Esposito ◽  
Francesca Freyria ◽  
Marco Armandi ◽  
Tanveer Gadhi ◽  
...  
Keyword(s):  
Tio2 Nanoparticles ◽  
Reverse Micelle ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Actual State ◽  
Test Reaction ◽  
Potential Measurement ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Mo Content

TiO2 nanoparticles containing 0.0, 1.0, 5.0, and 10.0 wt.% Mo were prepared by a reverse micelle template assisted sol–gel method allowing the dispersion of Mo atoms in the TiO2 matrix. Their textural and surface properties were characterized by means of X-ray powder diffraction, micro-Raman spectroscopy, N2 adsorption/desorption isotherms at −196 °C, energy dispersive X-ray analysis coupled to field emission scanning electron microscopy, X-ray photoelectron spectroscopy, diffuse reflectance UV–Vis spectroscopy, and ζ-potential measurement. The photocatalytic degradation of Rhodamine B (under visible light and low irradiance) in water was used as a test reaction as well. The ensemble of the obtained experimental results was analyzed in order to discover the actual state of Mo in the final materials, showing the occurrence of both bulk doping and Mo surface species, with progressive segregation of MoOx species occurring only at a higher Mo content.

Synthesis, Characterization and Photocatalytic Activity of Nb-Doped TiO2 Nanoparticles

2012 ◽  
Vol 455-456 ◽  
pp. 110-114 ◽  
Author(s):  
Xuan Dong Li ◽  
Xi Jiang Han ◽  
Wen Ying Wang ◽  
Xiao Hong Liu ◽  
Yan Wang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Doped Tio2 ◽  
X Ray ◽  
Vis Spectroscopy

Nb-doped TiO2 powders with different concentrations of Nb have been synthesized by a sol-gel method and characterized by a series of technologies including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis spectroscopy. The photocatalytic activity of Nb-doped TiO2 is evaluated by degradation efficiency of methyl orange in aqueous solution. The results indicate that the photocatalytic activity of Nb-doped TiO2 synthesized with a Nb/Ti molar ratio of 5% is higher than that of TiO2 under the visible light.

scholarly journals Catalytic performance of the Ce-doped LaCoO3 perovskite nanoparticles

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Anees A. Ansari ◽  
Syed F. Adil ◽  
Manawwer Alam ◽  
N. Ahmad ◽  
Mohamed E. Assal ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Catalytic Performance ◽  
Temperature Program Reduction ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Optimum Reaction ◽  
Perovskite Nanoparticles

Abstract A series of La1-xCexCoO3 perovskite nanoparticles with rhombohedral phases was synthesized via sol–gel chemical process. X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Electron Diffraction Spectroscopy (EDS), Thermogravimetric Analysis (TGA), UV–Vis spectroscopy, Fourier Transform Infrared spectra (FTIR), Nitrogen Adsorption/desorption Isotherm, Temperature Program Reduction/Oxidation (TPR/TPO), X-ray Photoelectron Spectroscopy (XPS) techniques were utilized to examine the phase purity and chemical composition of the materials. An appropriate doping quantity of Ce ion in the LaCoO3 matrix have reduced the bond angle, thus distorting the geometrical structure and creating oxygen vacancies, which thus provides fast electron transportation. The reducibility character and surface adsorbed oxygen vacancies of the perovskites were further improved, as revealed by H2-TPR, O2-TPD and XPS studies. Furthermore, the oxidation of benzyl alcohol was investigated using the prepared perovskites to examine the effect of ceria doping on the catalytic performance of the material. The reaction was carried out with ultra-pure molecular oxygen as oxidant at atmospheric pressure in liquid medium and the kinetics of the reaction was investigated, with a focus on the conversion and selectivity towards benzaldehyde. Under optimum reaction conditions, the 5% Ce doped LaCoO3 catalyst exhibited enhanced catalytic activity (i.e., > 35%) and selectivity of > 99%, as compared to the other prepared catalysts. Remarkably, the activity of catalyst has been found to be stable after four recycles.

scholarly journals Microwave synthesis of high-quality and uniform 4 nm ZnFe2O4 nanocrystals for application in energy storage and nanomagnetics

2016 ◽  
Vol 7 ◽  
pp. 1350-1360 ◽  
Author(s):  
Christian Suchomski ◽  
Ben Breitung ◽  
Ralf Witte ◽  
Michael Knapp ◽  
Sondes Bauer ◽  
...  
Keyword(s):  
Energy Storage ◽  
Photoelectron Spectroscopy ◽  
Zinc Ferrite ◽  
Sol Gel ◽  
High Capacity ◽  
Spherical Shape ◽  
Freezing Temperature ◽  
Ex Situ ◽  
Edge Structure ◽  
X Ray

Magnetic nanocrystals with a narrow size distribution hold promise for many applications in different areas ranging from biomedicine to electronics and energy storage. Herein, the microwave-assisted sol–gel synthesis and thorough characterization of size-monodisperse zinc ferrite nanoparticles of spherical shape is reported. X-ray diffraction, 57Fe Mössbauer spectroscopy and X-ray photoelectron spectroscopy all show that the material is both chemically and phase-pure and adopts a partially inverted spinel structure with Fe3+ ions residing on tetrahedral and octahedral sites according to (Zn0.32Fe0.68)tet[Zn0.68Fe1.32]octO4±δ. Electron microscopy and direct-current magnetometry confirm the size uniformity of the nanocrystals, while frequency-dependent alternating-current magnetic susceptibility measurements indicate the presence of a superspin glass state with a freezing temperature of about 22 K. Furthermore, as demonstrated by galvanostatic charge–discharge tests and ex situ X-ray absorption near edge structure spectroscopy, the as-prepared zinc ferrite nanocrystals can be used as a high-capacity anode material for Li-ion batteries, showing little capacity fade – after activation – over hundreds of cycles. Overall, in addition to the good material characteristics, it is remarkable that the microwave-based synthetic route is simple, easily reproducible and scalable.

scholarly journals Synthesis and Characterization of Boron, Copper, and Zinc-Doped Hydroxyapatite by Sol-Gel Method: Research of Absorption and Thermal Behavior

2021 ◽  
Author(s):  
Dilek Çanakçı
Keyword(s):  
Thermal Behavior ◽  
Sol Gel ◽  
Absorption Bands ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Copper And Zinc ◽  
Vis Spectroscopy ◽  
Metal Doped

Abstract In this study, hydroxyapatites reinforced with Boron, Copper and Zinc at different rates were produced using the sol-gel method. Different amounts of metal during the production of hydroxyapatite were used to observe the amount of crystallization and morphological differences in their structures. The characterization of the metal-doped HAp was carried out by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX). The data indicated that the Ca/P stoichiometric ratios of the samples varied between 1.71 and 2, so their morphologies were different from each other. The absorption behavior of novel metal-doped HAp samples was evaluated at room temperature by UV-vis spectroscopy. In the absorption spectra of the samples, absorption bands formed in similar regions. In addition, the thermal behavior of HAp samples was investigated using TG/DTA techniques. The results of the analysis showed that heat resistance of the new synthesized samples was quite high.

scholarly journals Bulk Versus Surface Modification of Alumina with Mn and Ce Based Oxides for CH4 Catalytic Combustion

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1771 ◽  
Author(s):  
Stefan Neatu ◽  
Mihaela M. Trandafir ◽  
Adelina Stănoiu ◽  
Ovidiu G. Florea ◽  
Cristian E. Simion ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Combustion ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Catalytic Combustion Of Methane ◽  
Adsorption Desorption

This study presents the synthesis and characterization of lanthanum-modified alumina supported cerium–manganese mixed oxides, which were prepared by three different methods (coprecipitation, impregnation and citrate-based sol-gel method) followed by calcination at 500 °C. The physicochemical properties of the synthesized materials were investigated by various characterization techniques, namely: nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and H2–temperature programmed reduction (TPR). This experimental study demonstrated that the role of the catalytic surface is much more important than the bulk one. Indeed, the incipient impregnation of CeO2–MnOx catalyst, supported on an optimized amount of 4 wt.% La2O3–Al2O3, provided the best results of the catalytic combustion of methane on our catalytic micro-convertors. This is mainly due to: (i) the highest pore size dimensions according to the Brunauer-Emmett-Teller (BET) investigations, (ii) the highest amount of Mn4+ or/and Ce4+ on the surface as revealed by XPS, (iii) the presence of a mixed phase (Ce2MnO6) as shown by X-ray diffraction; and (iv) a higher reducibility of Mn4+ or/and Ce4+ species as displayed by H2–TPR and therefore more reactive oxygen species.

Preparation and Characterization of N Doped TiO2/ Sepiolite Composite Materials

2011 ◽  
Vol 284-286 ◽  
pp. 597-600
Author(s):  
Dai Mei Chen ◽  
Hai Peng Ji ◽  
Jian Xin Wang ◽  
Jian Chen ◽  
Xin Long Luan ◽  
...  
Keyword(s):  
Composite Materials ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nitrogen Doped ◽  
Nitrogen Contents ◽  
Scanning Electron ◽  
Oxygen Atoms

Nitrogen doped TiO2/sepiolite composite materials (N-TiO2/sep) with different nitrogen contents were prepared by a sol-gel method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), respectively. XRD and SEM results showed that anatase-TiO2nanoparticles were distributed homogenously on the surface of sepiolite. XPS revealed that N atoms could incorporate into the lattice of anatase TiO2substituting the oxygen atoms sites of oxygen atoms.

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