scholarly journals Synthesis of SiO2-TiO2:Yb3+ glass-ceramics and characterization of structure and optical properties

2017 ◽  
Vol 1 (T1) ◽  
pp. 114-121
Author(s):  
Thanh Tat Huynh ◽  
Van Thi Thanh Tran
Keyword(s):  
Sol Gel ◽  
Glass Ceramics ◽  
Xrd Analysis ◽  
Silica Matrix ◽  
Photoluminescence Intensity ◽  
Raman Spectroscopic ◽  
Characteristic Emission ◽  
Ft Ir ◽  
Average Size ◽  
20 Nm

In this work, the monoliths of 85 % SiO2-15 % TiO2 doped Yb3+ ions at different contents have been prepared by sol-gel method. The measurement of FT-IR, Raman spectroscopic and XRD analysis show the formation of anatase TiO2 nanocrystals with average size about 15–20 nm in silica matrix. Moreover, the pyrochlore crystals of Yb2Ti2O7 begin to form in the samples when content of Yb3+ reaches to 1 mol %. TiO2 Yb3+ 2F7/2 2F5/2 truyền năng lƣợng kích thích UV EV EC mức khuyết tật 974 nm The energy transferred from TiO2 crystals to Yb3+ ions is proven by the characteristic emission spectrum of Yb3+ at the wavelength of 980 nm when the samples are excited by the wavelength of 300 nm. The photoluminescence intensity is highest at 0.1% mol of Yb3+ and gradually decreases with doping content

Synthesis and Characterization of Sol–Gel Prepared Silver Nanoparticles

2014 ◽  
Vol 13 (01) ◽  
pp. 1450004 ◽  
Author(s):  
Dharamvir Singh Ahlawat ◽  
Rekha Kumari ◽  
Rachna ◽  
Indu Yadav
Keyword(s):  
Silver Nanoparticles ◽  
Absorption Spectra ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Silica Matrix ◽  
Silver Clusters ◽  
Different Temperatures ◽  
Uv Visible ◽  
Average Size

Silver nanoparticles (SNPs) have been successfully prepared using sol–gel method by annealing the sample at 550°C for 30 min. The SNPs were not confirmed by X-ray diffraction (XRD) analysis when the annealing temperature was considered at 450°C. They were also not confirmed without calcination of the sample. The physical mechanism of silver clusters formation in the densified silica matrix with respect to thermal treatment has been understood. The presence of silver metal in the silica matrix was confirmed by XRD analysis and TEM image of the samples. The average size of nanoparticles dispersed in silica matrix was determined as 10.2 nm by the XRD technique. The synthesized nanocomposites were also characterized by UV-Visible spectroscopy with a peak in the absorption spectra at around 375 nm. The distribution of particle size has been reported here in the range from 8 nm to 25 nm by TEM observations of the sample prepared at 550°C. The spherically smaller size (≈10 nm) SNPs have reported the surface plasmons resonance (SPR) peak less than or near to 400 nm due to blue-shifting and effect of local refractive index. Without annealing the silica samples the absorption spectra does not show any peak around 375 nm. The FTIR spectroscopy of the three types of samples prepared at different temperatures (room temperature, 450°C and 550°C) has also been reported. This spectra have provided the identification of different chemical groups in the prepared samples. It has been predicted that the size of SNPs by XRD, UV-Visible and TEM results have agreed well with each other. It may be concluded that formation of SNPs is a function of annealing temperature.

scholarly journals Upconversion Luminescence of Silica–Calcia Nanoparticles Co-doped with Tm3+ and Yb3+ Ions

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 937
Author(s):  
Katarzyna Halubek-Gluchowska ◽  
Damian Szymański ◽  
Thi Ngoc Lam Tran ◽  
Maurizio Ferrari ◽  
Anna Lukowiak
Keyword(s):  
Energy Transfer ◽  
Near Infrared ◽  
Upconversion Luminescence ◽  
Sol Gel ◽  
Emission Spectra ◽  
Transmission Electron ◽  
Characteristic Emission ◽  
Diffraction Patterns ◽  
Size Of Particles ◽  
Average Size

Looking for upconverting biocompatible nanoparticles, we have prepared by the sol–gel method, silica–calcia glass nanopowders doped with different concentration of Tm3+ and Yb3+ ions (Tm3+ from 0.15 mol% up to 0.5 mol% and Yb3+ from 1 mol% up to 4 mol%) and characterized their structure, morphology, and optical properties. X-ray diffraction patterns indicated an amorphous phase of the silica-based glass with partial crystallization of samples with a higher content of lanthanides ions. Transmission electron microscopy images showed that the average size of particles decreased with increasing lanthanides content. The upconversion (UC) emission spectra and fluorescence lifetimes were registered under near infrared excitation (980 nm) at room temperature to study the energy transfer between Yb3+ and Tm3+ at various active ions concentrations. Characteristic emission bands of Tm3+ ions in the range of 350 nm to 850 nm were observed. To understand the mechanism of Yb3+–Tm3+ UC energy transfer in the SiO2–CaO powders, the kinetics of luminescence decays were studied.

scholarly journals Synthesis of Silica-Salen Derivative from Rice Husk Ash and its Use for Extraction of Divalent Metal Ions Co(II), Ni(II) and Cu(II)

2019 ◽  
Vol 20 (1) ◽  
pp. 16 ◽  
Author(s):  
Duha Hussien Attol ◽  
Hayder Hamied Mihsen
Keyword(s):  
Metal Ions ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Divalent Metal Ions ◽  
Prepared Compound ◽  
Absorption Bands ◽  
Pseudo Second Order ◽  
Ft Ir

Rice husk ash (RHA) was used to prepare sodium silicate, which in turn was functionalized with 3-(chloropropyl)triethoxysilane employing the sol-gel technique to form RHACCl. Chloro group in RHACCl was replaced with iodo group forming RHACI. Ethylenediamine was immobilized on RHACI in order to prepare it for the reaction with salicylaldehyde to form a silica derivative-salen. FT-IR analysis indicated the presence of secondary amine and –NH and C=N absorption bands. XRD analysis revealed the occurrence of the broad diffused peak with maximum intensity at 22–23° (2θ). BET measurements showed also that the surface area of the prepared compound is 274.55 m2/g. Elemental analysis proved the existence of nitrogen in the structure of the prepared compound. The silica derivative-salen showed high potential for extraction and removal of heavy contaminating metal ions Ni(II), Cu(II), and Co(II) from aqueous solutions. The kinetic study demonstrates that the adsorption of the metal ions follows the pseudo-second order.

scholarly journals SiO2-SnO2:Er3+ Glass-Ceramic Monoliths

2018 ◽  
Author(s):  
Lam Thi Ngoc Tran ◽  
Damiano Massella ◽  
Lidia Zur ◽  
Alessandro Chiasera ◽  
Stefano Varas ◽  
...  
Keyword(s):  
Rare Earth ◽  
Optical Sensors ◽  
Tin Dioxide ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Building Blocks ◽  
Spectroscopic Properties ◽  
Silica Matrix ◽  
Rare Earth Ions ◽  
Planar Waveguides

The development of efficient luminescent systems, such as microcavities, solid state lasers, integrated optical amplifiers, optical sensors is the main topic in glass photonics. The building blocks of these systems are glass-ceramics activated by rare earth ions because they exhibit specific morphologic, structural and spectroscopic properties. Among various materials that could be used as nanocrystals to be imbedded in silica matrix, tin dioxide presents some interesting peculiarities, e.g. the presence of tin dioxide nanocrystals allows increase in both solubility and emission of rare earth ions. Here, we focus our attention on Er3+ - doped silica – tin dioxide photonic glass-ceramics fabricated by sol-gel route. Although the SiO2-SnO2:Er3+ could be fabricated in different geometrical systems: thin films, monoliths and planar waveguides we herein limit ourselves to the monoliths. The effective role of tin dioxide as luminescence sensitizer for Er3+ ions is confirmed by spectroscopic measurements and detailed fabrication protocols are discussed.

scholarly journals Magnetite-Functionalized Horse Dung Humic Acid (HDHA) for the Uptake of Toxic Lead(II) from Artificial Wastewater

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Rahmat Basuki ◽  
Bambang Rusdiarso ◽  
Sri Juari Santosa ◽  
Dwi Siswanta
Keyword(s):  
Humic Acid ◽  
Xrd Analysis ◽  
Desorption Process ◽  
X Ray ◽  
Ft Ir ◽  
Magnetic Strength ◽  
The Stability ◽  
Ir Study ◽  
Average Size ◽  
Adsorption Rates

Magnetite-functionalized horse dung humic acid (HDHA) has been successfully prepared by the coprecipitation method, and the as-prepared adsorbent (MHDHA) has been applied as an easy-handling adsorbent for toxic Pb(II) in artificial wastewater. The MHDHA was characterized by Fourier transform-infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), and vibrating sample magnetometer (VSM). The FT-IR study showed that the MHDHA had the characteristics peaks of HA and Fe-O stretching. The XRD analysis revealed that the MHDHA had the 2 θ characteristic for magnetite. The TEM image and EDX analysis exhibited that the MHDHA with an average size of ∼14 nm was partially aggregated and contained ( w / w ) 9.89% carbon, 2.89% nitrogen, and 32.74% oxygen based on functional groups of HDHA. The stability improvement of MHDHA was showed by decreasing HDHA dissolved from 95% to less than 30% at pH 12 after magnetite functionalization. The post-adsorption handling improvement was evidenced by easy and quick retraction by an external magnet with a 62.95 emu/g magnetic strength value. The adsorption capacities were influenced by the pH and ionic strength, whilst the adsorption rates were well simulated by the Ho pseudo-second-order model. The removal uptake of Pb(II) ions increased when the initial concentration was increased and fitted well with the Langmuir isotherm model when the monolayer adsorption capacity was 2.78 × 10 − 4   mol / g (equal to 57.64 mg/g). The value of Dubinin-Radushkevich adsorption energy ( E D − R ) found in this study was 14.78 kJ/mol, which implied that ion exchange is the main mechanism involved in the adsorption process. The regeneration studies of MHDHA show that there was no significant change in composition, morphology, crystallinity, and functional group after five consecutive cycles of the adsorption-desorption process.

scholarly journals Rhodium Nanoparticles Incorporated Mesoporous Silica as an Active Catalyst for Cyclohexene Hydrogenation under Ambient Conditions

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 925
Author(s):  
Mohamed S. Hamdy ◽  
Abdullah M. Alhanash ◽  
Mhamed Benaissa ◽  
Ali Alsalme ◽  
Fahad A. Alharthi ◽  
...  
Keyword(s):  
Reaction Temperature ◽  
Sol Gel ◽  
Three Dimensional ◽  
Silica Matrix ◽  
Hydrogen Gas ◽  
Ambient Conditions ◽  
Consecutive Reaction ◽  
Rhodium Nanoparticles ◽  
Optimization Parameters ◽  
Average Size

Rhodium (Rh) nanoparticles were embedded in the mesopores of TUD-1 siliceous material and denoted as Rh-TUD-1. Five samples of Rh-TUD-1 were prepared with different loadings of Rh that ranged from 0.1 to 2 wt% using the sol-gel technique. The prepared samples were characterized by means of several chemical and physical techniques. The obtained characterization results show the formation of highly distributed Rh0 nanoparticles with an average size ranging from 3 to 5 nm throughout the three-dimensional silica matrix of TUD-1. The catalytic activity of the prepared catalysts was evaluated in the solvent-free hydrogenation of cyclohexene to cyclohexane at room temperature using 1atm of hydrogen gas. The obtained catalytic results confirm the high activity of Rh-TUD-1, in which a turn over frequency (TOF) ranging from 4.94 to 0.54 s−1 was obtained. Moreover, the change in reaction temperature during the reaction was monitored, and it showed an obvious increase in the reaction temperature as an indication of the spontaneous and exothermic nature of the reactions. Other optimization parameters, such as the substrate/catalyst ratio, and performing the reaction under non-ambient conditions (temperature = 60 °C and hydrogen pressure = 5 atm) were also investigated. Rh-TUD-1 exhibited a high stability in a consecutive reaction of five runs under either ambient or non-ambient conditions.

Sol-Gel Synthesis of FHA Nanoparticles and CDHA Agglomerates from a Mixture with a Nonstochiometric Ca/P Ratio

2008 ◽  
Vol 396-398 ◽  
pp. 607-610 ◽  
Author(s):  
R. Jahandideh ◽  
Aliasghar Behnamghader ◽  
M. Rangie ◽  
A. Youzbashi ◽  
S. Joughehdoust ◽  
...  
Keyword(s):  
Sol Gel ◽  
Calcium Nitrate ◽  
Triethyl Phosphite ◽  
Ammonium Fluoride ◽  
Powder Morphology ◽  
Dispersed Particles ◽  
Ft Ir ◽  
Xrd Patterns ◽  
Average Size ◽  
Sol Gel Synthesis

The aim of this study was to investigate the sol gel synthesis of HA/FA nanoparticles and the possible formation of TCP phase or unstoichiometric calcium deficient hydroxyapatite (CDHA) from the precursors with a Ca/P ratio of 1.62. In order to prepare the sol, the solutions of Triethyl phosphite, ammonium fluoride and calcium nitrate in ethanol were used respectively as P, F and Ca precursors. The crystallinity, particle and crystallite size, powder morphology, chemical structure and phase analysis were investigated by SEM, XRD, FT-IR and Zeta sizer experiment. A multiphase compound containing hydroxyapatite (HA) and fluoroapatite (FA) nanoparticles and calcium deficient hudroxyapatite (CDHA) agglomerates was obtained. The size of the crystallites estimated from XRD patterns using Scherrer equation and the crystallinity of HA phase were about 5 nm and 66% respectively. The zeta sizer experiments for the dispersed particles in its own conditions showed an average size of 98 nm.

scholarly journals Characterization of Modified Magnetite Nanoparticles for Albumin Immobilization

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
A. K. Bordbar ◽  
A. A. Rastegari ◽  
R. Amiri ◽  
E. Ranjbakhsh ◽  
M. Abbasi ◽  
...  
Keyword(s):  
Sol Gel ◽  
Xrd Analysis ◽  
Covalent Immobilization ◽  
Initial Value ◽  
X Ray ◽  
Buffer Solutions ◽  
Transmission Electron ◽  
Ft Ir ◽  
Chemical Coprecipitation Method

Magnetite Fe3O4 nanoparticles (NPs) were prepared by chemical coprecipitation method. Silica-coated magnetite NPs were prepared by sol-gel reaction, subsequently coated with 3-aminopropyltriethoxysilane (APTES) via silanization reaction, and then were activated with 2,4,6-trichloro-1,3,5-triazine (TCT) and covalently immobilized with bovine serum albumin (BSA). The size and structure of the particles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and dynamic light scattering (DLS) techniques. The immobilization was confirmed by Fourier transform infrared spectroscopy (FT-IR). XRD analysis showed that the binding process has not done any phase change to Fe3O4. The immobilization time for this process was 4 h and the amount of immobilized BSA for the initial value of 1.05 mg BSA was about 120 mg/gr nanoparticles. Also, the influences of three different buffer solutions and ionic strength on covalent immobilization were evaluated.

scholarly journals New SiO2/Caffeic Acid Hybrid Materials: Synthesis, Spectroscopic Characterization, and Bioactivity

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 394 ◽  
Author(s):  
Michelina Catauro ◽  
Federico Barrino ◽  
Giovanni Dal Poggetto ◽  
Giuseppina Crescente ◽  
Simona Piccolella ◽  
...  
Keyword(s):  
Caffeic Acid ◽  
Hybrid Materials ◽  
Structural Changes ◽  
Sol Gel ◽  
Functional Materials ◽  
Spectroscopic Characterization ◽  
Silica Matrix ◽  
Materials Synthesis ◽  
Vis Spectroscopy ◽  
Ft Ir

The sol–gel route represents a valuable technique to obtain functional materials, in which organic and inorganic members are closely connected. Herein, four hybrid materials, containing caffeic acid entrapped in a silica matrix at 5, 10, 15, and 20 wt.%, were synthesized and characterized through Fourier-Transform Infrared (FT-IR) and Ultraviolet-Visible (UV–Vis) spectroscopy. FT-IR analysis was also performed to evaluate the ability to induce the hydroxyapatite nucleation. Despite some structural changes occurring on the phenol molecular skeleton, hybrid materials showed scavenging properties vs. 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2′-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid) radical cation (ABTS•+), which was dependent on the tested dose and on the caffeic acid wt.%. The SiO2/caffeic acid materials are proposed as valuable antibacterial agents against Escherichia coli and Enterococcus faecalis.

Study on Synthesis and Characterization of Cu-Ni Doped TiO2 by Sol-Gel Hydrothermal

2014 ◽  
Vol 925 ◽  
pp. 396-400 ◽  
Author(s):  
Robabeh Bashiri ◽  
Norani Muti Mohamed ◽  
Chong Fai Kait ◽  
Suriati Sufian
Keyword(s):  
Crystal Size ◽  
Sol Gel ◽  
Visible Region ◽  
Xrd Analysis ◽  
Total Surface Area ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Metals Loading ◽  
20 Nm

Titania (TiO2) as a semiconductor has been intensively studied during the last decades. Regardless of its superior photocatalytic performance and extensive environmental applications, it has a wide bandgap which lead to a photocatalytic activity only in ultraviolet (UV) irradiation. To shift the activity of TiO2 to visible region, a series of monometallic and bimetallic doped TiO2 was prepared with 10wt% total metals loading. The photocatalysts were synthesized by sol-gel associated via hydrothermal method. The properties of the photocatalysts such as crystal size, surface morphology, total surface area, chemical state of the elements, and bandgap were investigated by using thermogravimetric analysis (TGA), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Brunauer–Emmett–Teller (BET) measurement. XRD analysis showed that all samples displayed anatase (101) as a main phase of TiO2 with average crystal size between 10-16 nm in a good agreement with the TEM results. The FESEM images show spherical particles less than 20 nm in size. The BET results indicated that all samples are mesoporous. The band gap of Ni-Cu/TiO2 is reduced to 2.65 eV with more absorbance in the visible region compared to those of cu/TiO2 and Ni/TiO2.

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