scholarly journals On the Reconstruction Peculiarities of Sol–Gel Derived Mg2−xMx/Al1 (M = Ca, Sr, Ba) Layered Double Hydroxides

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 470 ◽  
Author(s):  
Ligita Valeikiene ◽  
Marina Roshchina ◽  
Inga Grigoraviciute-Puroniene ◽  
Vladimir Prozorovich ◽  
Aleksej Zarkov ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Pore Diameter ◽  
Sol Gel ◽  
Earth Metal ◽  
Nitrogen Adsorption ◽  
Xrd Analysis ◽  
X Ray ◽  
Double Hydroxides ◽  
Synthesized Materials ◽  
First Time

In this study, the reconstruction peculiarities of sol–gel derived Mg2−xMx/Al1 (M = Ca, Sr, Ba) layered double hydroxides were investigated. The mixed metal oxides (MMO) were synthesized by two different routes. Firstly, the MMO were obtained directly by heating Mg(M)–Al–O precursor gels at 650 °C, 800 °C, and 950 °C. These MMO were reconstructed to the Mg2−xMx/Al1 (M = Ca, Sr, Ba) layered double hydroxides (LDHs) in water at 50 °C for 6 h (pH 10). Secondly, in this study, the MMO were also obtained by heating reconstructed LDHs at the same temperatures. The synthesized materials were characterized using X-ray powder diffraction (XRD) analysis and scanning electron microscopy (SEM). Nitrogen adsorption by the Brunauer, Emmett, and Teller (BET) and Barrett, Joyner, and Halenda (BJH) methods were used to determine the surface area and pore diameter of differently synthesized alkaline earth metal substituted MMO compounds. It was demonstrated for the first time that the microstructure of reconstructed MMO from sol–gel derived LDHs showed a “memory effect”.

scholarly journals Undoped and Eu3+ Doped Magnesium-Aluminium Layered Double Hydroxides: Peculiarities of Intercalation of Organic Anions and Investigation of Luminescence Properties

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 736 ◽  
Author(s):  
Aurelija Smalenskaite ◽  
Lina Pavasaryte ◽  
Thomas Yang ◽  
Aivaras Kareiva
Keyword(s):  
Layered Double Hydroxides ◽  
Organic Anion ◽  
Sol Gel ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Organic Guests ◽  
Double Hydroxides ◽  
Scanning Electron

The Mg3/Al and Mg3/Al0.99Eu0.01 layered double hydroxides (LDHs) were fabricated using a sol-gel chemistry approach and intercalated with different anions through ion exchange procedure. The influence of the origin of organic anion (oxalate, laurate, malonate, succinate, tartrate, benzoate, 1,3,5-benzentricarboxylate (BTC), 4-methylbenzoate (MB), 4-dimethylaminobenzoate (DMB) and 4-biphenylacetonate (BPhAc)) on the evolution of the chemical composition of the inorganic-organic LDHs system has been investigated. The obtained results indicated that the type and arrangement of organic guests between layers of the LDHs influence Eu3+ luminescence in the synthesized different hybrid inorganic–organic matrixes. For the characterization of synthesis products X-ray diffraction (XRD) analysis, infrared (FTIR) spectroscopy, fluorescence spectroscopy (FLS), and scanning electron microscopy (SEM), were used.

scholarly journals Sol–Gel Synthesis and Characterization of Coatings of Mg-Al Layered Double Hydroxides

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3738 ◽  
Author(s):  
A. Smalenskaite ◽  
M. M. Kaba ◽  
I. Grigoraviciute-Puroniene ◽  
L. Mikoliunaite ◽  
A. Zarkov ◽  
...  
Keyword(s):  
Thin Films ◽  
Layered Double Hydroxides ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Dip Coating ◽  
Dipping Process ◽  
Synthetic Approaches ◽  
Sol Gel Synthesis ◽  
Double Hydroxides ◽  
Steel Substrates

In this study, new synthetic approaches for the preparation of thin films of Mg-Al layered double hydroxides (LDHs) have been developed. The LDHs were fabricated by reconstruction of mixed-metal oxides (MMOs) in deionized water. The MMOs were obtained by calcination of the precursor gels. Thin films of sol–gel-derived Mg-Al LDHs were deposited on silicon and stainless-steel substrates using the dip-coating technique by a single dipping process, and the deposited film was dried before the new layer was added. Each layer in the preparation of the Mg-Al LDH multilayers was separately annealed at 70 °C or 300 °C in air. Fabricated Mg-Al LDH coatings were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and atomic force microscopy (AFM). It was discovered that the diffraction lines of Mg3Al LDH thin films are sharper and more intensive in the sample obtained on the silicon substrate, confirming a higher crystallinity of synthesized Mg3Al LDH. However, in both cases the single-phase crystalline Mg-Al LDHs have formed. To enhance the sol–gel processing, the viscosity of the precursor gel was increased by adding polyvinyl alcohol (PVA) solution. The LDH coatings could be used to protect different substrates from corrosion, as catalyst supports, and as drug-delivery systems in medicine.

Preparation of TiO2/Ga2O3 Nanowires by a Sol-Gel-Solvothermal Method

2010 ◽  
Vol 663-665 ◽  
pp. 965-968
Author(s):  
Yue Hui Wang ◽  
Dong Jun Wang ◽  
Ai Jun Song ◽  
Zhi Gang Zhang ◽  
Shi Tao Song
Keyword(s):  
Electron Microscopy ◽  
Near Infrared ◽  
Solvothermal Method ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Tetrabutyl Titanate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
First Time

TiO2/Ga2O3 nanowires were successfully prepared by a sol–gel-solvothermal method using tetrabutyl titanate as precursor, alcohol as solvent, Ga2O3 as templet and dopants, alginate as dispersant. The structures, morphologies,compositions and catalytic activity of products have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy ( FESEM ), nitrogen adsorption test, ultraviolet-visible near-infrared spectroscopy (UV–vis–NIR ),energy dispersive X-ray (EDX) analysis and spectrophotometer. The results revealed that the as-synthesized TiO2/Ga2O3 nanowires grew along [001] direction,which is reported for the first time, and the as-prepared product had better optical activity than TiO2 nanoparticles. Finally, the nanowires have a good adsorption capacity of 128.2 m2/g tested through nitrogen adsorption.

scholarly journals Synthesis and characterization of layered double hydroxides with different cations (Mg, Co, Ni, Al), decomposition and reformation of mixed metal oxides to layered structures

2011 ◽  
Vol 9 (2) ◽  
pp. 275-282 ◽  
Author(s):  
Kristina Klemkaite ◽  
Igoris Prosycevas ◽  
Ricardas Taraskevicius ◽  
Alexander Khinsky ◽  
Aivaras Kareiva
Keyword(s):  
Metal Oxides ◽  
Layered Double Hydroxides ◽  
Xrd Analysis ◽  
Layered Structures ◽  
Magnesium Nitrate ◽  
Mixed Metal Oxides ◽  
X Ray ◽  
Mixed Metal ◽  
Different Temperatures ◽  
Double Hydroxides

AbstractThree layered double hydroxides (LDH) [Mg1−xAlx(OH)2]x+(Am−)x/m]·nH2O and [MII 1−xMIII x (OH)2]x+(Am−)x/m]·nH2O (MII — Mg, Co, Ni; MIII — Al; A — CO3 2−) were successfully synthesized by the low supersaturation method. The as-synthesized LDH samples were thermally decomposed and the derived mixed metal oxides reformed back to layered structures in water and magnesium nitrate media at different temperatures. All synthesized samples were characterized by X-ray diffraction (XRD) analysis, thermogravimetric (TG) analysis, X-ray fluorescence (XRF) analysis and scanning electron microscopy (SEM). The results of XRD and XRF analyses showed that single-phase layered double hydroxides were formed during synthesis and reformation. It was demonstrated, that a partially substituted by cobalt and nickel LDH samples also show memory effect. The crystallite size of regenerated LDH depends on the regeneration media, temperature and chemical composition. The LDH samples after regeneration consist of large particles with sharp edges along with a large amount of smaller particles

scholarly journals Dielectric properties of Bi-substituted LDHs synthesized by co-precipitation and sol-gel methods

2019 ◽  
Vol 37 (2) ◽  
pp. 190-195 ◽  
Author(s):  
Denis Sokol ◽  
Maksim Ivanov ◽  
Andrei N. Salak ◽  
Robertas Grigalaitis ◽  
Juras Banys ◽  
...  
Keyword(s):  
Sol Gel ◽  
Xrd Analysis ◽  
Precipitation Method ◽  
Complexing Agent ◽  
Mixed Metal Oxides ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Precipitation ◽  
Double Hydroxides ◽  
Gel Processing

AbstractMagnesium-aluminum-bismuth layered double hydroxides (Mg3Al1−xBix; LDHs) were prepared using both coprecipitation and sol-gel methods. For the preparation of Mg/Al/Bi LDH by the co-precipitation method, the appropriate amounts of dissolved starting materials (Al(NO3)3 · 9H2O, Mg(NO3)2 · 6H2O and Bi(NO3)3 · 5H2O) were mixed with a solution of NaHCO3:NaOH. In the sol-gel processing, the precursor Mg–Al–Bi–O gels were synthesized using the same starting materials and ethylene glycol as complexing agent. The mixed-metal oxides obtained by subsequent heating of Mg–Al–Bi–O gels at 650 °C were reconstructed to Mg3Al1−xBix LDHs in water at 80 °C. All the synthesized products were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and dielectric measurements.

Preparation and Characterization of New Hybrid Materials Type Layered Double Hydroxides Intercalated with 4,6-dinitro-o-cresols

2008 ◽  
Vol 59 (2) ◽  
pp. 165-167
Author(s):  
Mihaela Frunza ◽  
Gabriela Lisa ◽  
Marcel Ionel Popa
Keyword(s):  
Layered Double Hydroxides ◽  
Chemical Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Physico Chemical ◽  
Double Hydroxides ◽  
Synthesized Materials ◽  
Analysis Point

The paper presents the tailoring synthesis and physico-chemical characterization of layered double hydroxides (LDH) intercalated with 4,6-dinitro-o-cresol (DNOC) by coprecipitation method. The X-ray diffraction (DRX), Fourier transformed infrared spectroscopy (FTIR) and thermogravimetric (TG -DTG) analysis point out the presence of the organic compound in the network structure of the synthesized materials. Considering together the pesticide activity of 4,6-dinitro-o-cresol and the biocompatibility of the layered double hydroxides the new synthesized materials could open interesting perspectives for obtaining more environmentally friendly insecticides.

scholarly journals Photocatalytic activity of Pr-modified TiO2 for the degradation of bisphenol A

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Denise S. Cordeiro ◽  
Fernando L. Cassio ◽  
Larissa Ciccotti ◽  
Thiago L. R. Hewer ◽  
Paola Corio ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Bisphenol A ◽  
Pore Diameter ◽  
Sol Gel ◽  
Bandgap Energy ◽  
Photocatalytic Efficiency ◽  
Average Pore ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Adsorption Desorption

AbstractPraseodymium doped TiO2 nanoparticles were successfully prepared by the sol–gel method and characterized by X-ray powder diffraction, N2 adsorption–desorption isotherm, and UV–vis spectroscopy. The effects of the dopant on the crystallite size, specific surface area, average pore diameter, pore volume, and bandgap energy were investigated. The photocatalytic activity of the catalysts was evaluated by bisphenol A degradation and mineralization, which is a representative endocrine disruptor. Furthermore, under visible light irradiation the Pr-modified TiO2 photocatalysts exhibited higher photocatalytic efficiency than unmodified TiO2. When praseodymium was loaded (1.0–5.0%) onto the surface of TiO2, the rates of degradation and mineralization were increased 3–5 times.

scholarly journals Photocatalytic Degradation of 2,4,6-Trichlorophenol by MgO–MgFe2O4 Derived from Layered Double Hydroxide Structures

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 454 ◽  
Author(s):  
Esthela Ramos-Ramírez ◽  
Francisco Tzompantzi-Morales ◽  
Norma Gutiérrez-Ortega ◽  
Héctor G. Mojica-Calvillo ◽  
Julio Castillo-Rodríguez
Keyword(s):  
Photocatalytic Degradation ◽  
Layered Double Hydroxides ◽  
X Ray Diffraction ◽  
Application Study ◽  
Toxic Compounds ◽  
X Ray ◽  
Thermally Activated ◽  
Double Hydroxide ◽  
Double Hydroxides ◽  
Scanning Electron

In recent years, the search for solutions for the treatment of water pollution by toxic compounds such as phenols and chlorophenols has been increasing. Phenols and their derivatives are widely used in the manufacture of pesticides, insecticides, paper, and wood preservers, among other things. Chlorophenols are partially biodegradable but not directly photodegradable by sunlight and are extremely toxic—especially 2,4,6-trichlorophenol, which is considered to be potentially carcinogenic. As a viable proposal to be applied in the treatment of water contaminated with 2,4,6-trichlorophenol, this paper presents an application study of the thermally activated Mg/Fe layered double hydroxides as photocatalysts for the mineralization of this contaminant. Activated Mg/Fe layered double hydroxides were characterized by X-ray diffraction, thermal analysis, N2 physisorption, and scanning electron microscopy with X-ray dispersive energy. The results of the photocatalytic degradation of 2,4,6-trichlorophenol in aqueous solution showed good photocatalytic activity, with an efficiency of degradation of up to 93% and mineralization of 82%; degradation values which are higher than that of TiO2-P25, which only reached 18% degradation. The degradation capacity is attributed to the structure of the MgO–MgFe2O4 oxides derived from double laminate hydroxide Mg/Fe. A path of degradation based on a mechanism of superoxide and hollow radicals is proposed.

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