Sol–gel synthesis of mesoporous CaFe2O4 photocathodes with hierarchical pore morphology

In this study, an aqueous sol-gel synthesis method and subsequent dip-coating technique were applied for the preparation of yttrium iron garnet (YIG), yttrium iron perovskite (YIP), and terbium iron perovskite (TIP) bulk and thin films. The monophasic highly crystalline different iron ferrite powders have been synthesized using this simple aqueous sol-gel process displaying the suitability of the method. In the next step, the same sol-gel solution was used for the fabrication of coatings on monocrystalline silicon (100) using a dip-coating procedure. This resulted, likely due to substrate surface influence, in all coatings having mixed phases of both garnet and perovskite. Thermogravimetric (TG) analysis of the precursor gels was carried out. All the samples were investigated by X-ray powder diffraction (XRD) analysis. The coatings were also investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Mössbauer spectroscopy. Magnetic measurements were also carried out.

Download Full-text

Sol–gel synthesis of 2-dimensional TiO2: self-assembly of Ti–oxoalkoxy–acetate complexes by carboxylate ligand directed condensation

Faraday Discussions ◽

10.1039/c9fd00108e ◽

2021 ◽

Cited By ~ 1

Author(s):

Ruohong Sui ◽

Connor E. Deering ◽

Rohen Prinsloo ◽

Christopher B. Lavery ◽

Nancy Chou ◽

...

Keyword(s):

Self Assembly ◽

Sol Gel ◽

Carboxylate Ligand ◽

Sol Gel Synthesis ◽

First Time

2-Dimensional TiO2 is synthesized for the first time by a sol–gel self-assembly of Ti–oxoalkoxy–acetate complexes.

Download Full-text

Sol-gel synthesis and characterization of Ag nanoparticles in ZrO2 thin films

Journal of Materials Research ◽

10.1557/jmr.2009.0314 ◽

2009 ◽

Vol 24 (8) ◽

pp. 2541-2546 ◽

Cited By ~ 7

Author(s):

Eisuke Yokoyama ◽

Hironobu Sakata ◽

Moriaki Wakaki

Keyword(s):

Thin Films ◽

Sol Gel ◽

Composite Films ◽

Dip Coating ◽

Molar Ratio ◽

X Ray Diffraction ◽

Silver Surface ◽

Molar Ratios ◽

Sol Gel Synthesis

ZrO2 thin films containing silver nanoparticles were prepared using the sol-gel method with Ag to Zr molar ratios [Ag]/[Zr] = 0.11, 0.25, 0.43, 0.67, 1.00, 1.50, and 2.33. After dip coating on glass substrate, coated films were annealed at 200 and 300 °C in air. X-ray diffraction peaks corresponding to crystalline Ag were observed, but a specific peak corresponding to ZrO2 was not observed. At the molar ratio [Ag]/[Zr] = 0.25, the particle size of Ag distributed broadly centered at 17 nm for an annealing temperature of 200 °C and at 25 nm for 300 °C. The films annealed in air at 200 °C showed an absorption band centered at 450 nm because of the silver surface plasmon resonance, whereas films heated at 300 °C in air caused a red shift of the absorption to 500 nm. The absorption peak was analyzed using the effective dielectric function of Ag-ZrO2 composite films modeled with the Maxwell-Garnett expression.

Download Full-text

A mesostructured hybrid CTA–silica carrier for curcumin delivery

Journal of Sol-Gel Science and Technology ◽

10.1007/s10971-020-05374-0 ◽

2020 ◽

Vol 96 (1) ◽

pp. 236-246

Author(s):

Marta Gallo ◽

Fabio Giudice ◽

Mauro Banchero ◽

Silvia Ronchetti ◽

Luigi Manna ◽

...

Keyword(s):

Water Solubility ◽

Uv Spectroscopy ◽

Sol Gel ◽

Topical Administration ◽

Release Mechanism ◽

Active Principle ◽

One Pot ◽

Drug Release Mechanism ◽

Sol Gel Synthesis ◽

First Time

Abstract Curcumin is a natural active principle with antioxidant, antibacterial and anti-inflammatory properties. Its use is limited by a low water solubility and fast degradation rate, which hinder its bioavailability. To overcome this problem, curcumin can be delivered through a carrier, which protects the drug molecule and enhances its pharmacological effects. The present work proposes a simple one-pot sol–gel synthesis to obtain a hybrid carrier for curcumin delivery. The hybrid consists of a mesostructured matrix of amorphous silica, which stabilizes the carrier, and hexadecyltrimethylammonium (CTA), a surfactant where curcumin is dissolved to increase its water solubility. The carrier was characterized in terms of morphology (FESEM), physicochemical properties (XRD, FTIR, UV spectroscopy) and release capability in pseudo-physiological solutions. Results show that curcumin molecules were entrapped, for the first time, in a silica-surfactant mesostructured hybrid carrier. The hybrid carrier successfully released curcumin in artificial sweat and in a phosphate buffer saline solution, so confirming its efficacy in increasing curcumin water solubility. The proposed drug release mechanism relies on the degradation of the carrier, which involves the concurrent release of silicon. This suggests strong potentialities for topical administration applications, since curcumin is effective against many dermal diseases while silicon is beneficial to the skin.

Download Full-text

A Molecular Route to Dip-coated Transition Metal Nitride Thin Films.

MRS Proceedings ◽

10.1557/proc-848-ff2.2 ◽

2004 ◽

Vol 848 ◽

Author(s):

Andrew W. Jackson ◽

Andrew L. Hector

Keyword(s):

Thin Films ◽

Transition Metal ◽

Spin Coating ◽

Sol Gel ◽

Particle Growth ◽

Dip Coating ◽

Stable Emulsion ◽

Transition Metal Nitride ◽

Sol Gel Synthesis ◽

Gel Processing

ABSTRACTThere is an increasing interest in sol-gel synthesis of nitrides. The ability to deposit films of these materials by dip- or spin-coating will increase the range of applications in which they are viable and is an important step toward general sol-gel processing of nitride materials.With transition metals, the ammono based analogue of the well established alkoxy route to gels is inherently difficult to control. Due to the basicity of the system, the overwhelming tendency is of the starting materials to favour particle growth which results in a precipitate rather than a stable emulsion, unless both environment and synthetic pathway are carefully controlled. Hence reports to date of sol-gel routes to nitrides describe production of powders. We report work on a sol-gel route to titanium nitride with the ammonolysis of titanium amides controlled by temperature and chemical moderators, resulting in stable emulsions useful for dip-coating.

Download Full-text

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

Materials ◽

10.3390/ma12223738 ◽

2019 ◽

Vol 12 (22) ◽

pp. 3738 ◽

Cited By ~ 3

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.

Download Full-text

Ga-Substituted Cobalt-Chromium Spinels as Ceramic Pigments Produced by Sol–Gel Synthesis

Crystals ◽

10.3390/cryst10121078 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1078

Author(s):

Egle Grazenaite ◽

Edita Garskaite ◽

Zivile Stankeviciute ◽

Eva Raudonyte-Svirbutaviciene ◽

Aleksej Zarkov ◽

...

Keyword(s):

Phase Composition ◽

Crystallite Size ◽

Single Phase ◽

Sol Gel ◽

Ceramic Pigments ◽

Blue Color ◽

Cobalt Chromium ◽

Light Blue ◽

Sol Gel Synthesis ◽

First Time

For the first time to the best of our knowledge, cobalt-chromium spinels CoCr2−xGaxO4 with different amounts of gallium (x = 0–2 with a step of 0.5) were synthesized via the aqueous sol–gel route as ceramic pigments. The phase composition, crystallite size, morphological features, and color parameters of new compositions and their corresponding ceramic glazes were investigated using XRD, CIELab, SEM, and optical microscopy. It was demonstrated that the formation of single-phase CoCr2−xGaxO4 samples was problematic. Full substitution of Cr3+ by Ga3+ ion in the spinel resulted in the formation of light blue powders, which yielded violetish blue color for the corresponding ceramic glaze.

Download Full-text

Sol–gel synthesis, structural and electrical properties of Li2CoSiO4 cathode material

Functional Materials Letters ◽

10.1142/s1793604714400013 ◽

2014 ◽

Vol 07 (06) ◽

pp. 1440001 ◽

Cited By ~ 3

Author(s):

Michał Świętosławski ◽

Marcin Molenda ◽

Piotr Natkański ◽

Piotr Kuśtrowski ◽

Roman Dziembaj ◽

...

Keyword(s):

Electrical Conductivity ◽

Sol Gel ◽

Lithium Ion ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Structural And Electrical Properties ◽

Potential Alternative ◽

Sol Gel Synthesis ◽

First Time

Polyanionic cathode materials for lithium-ion batteries start to be considered as potential alternative for layered oxide materials. Among them, Li 2 CoSiO 4, characterized by outstanding capacity and working voltage, seems to be an interesting substitute for LiFePO 4 and related systems. In this work, structural and electrical investigations of Li 2 CoSiO 4 obtained by sol–gel synthesis were presented. Thermal decomposition of gel precursor was studied using EGA (FTIR)-TGA method. Chemical composition of the obtained material was confirmed using X-ray diffraction and energy-dispersive X-ray spectroscopy. The morphology of β- Li 2 CoSiO 4 was studied using transmission electron microscopy. High temperature electrical conductivity of Li 2 CoSiO 4 was measured for the first time. Activation energies of the electrical conductivity of two Li 2 CoSiO 4 polymorphs (β and γ) were determined. The room temperature electrical conductivity of those materials was estimated as well.

Download Full-text

Formation of nanoscopic CaF2via a fluorolytic sol–gel process for antireflective coatings

Journal of Materials Chemistry C ◽

10.1039/c4tc02510e ◽

2015 ◽

Vol 3 (8) ◽

pp. 1716-1723 ◽

Cited By ~ 24

Author(s):

Alexander Rehmer ◽

Kerstin Scheurell ◽

Erhard Kemnitz

Keyword(s):

Sol Gel ◽

Nano Particles ◽

Antireflective Coatings ◽

Sol Gel Process ◽

Sol Gel Synthesis ◽

First Time

For the first time transparent antireflective CaF2-coatings were prepared from clear CaF2-sols obtained via the fluorolytic sol–gel synthesis and containing homo-dispersed CaF2 nano-particles.

Download Full-text

Two Synthetic Routes to The Formation of Tungsten Oxide Hybrid Compounds

MRS Proceedings ◽

10.1557/proc-847-ee13.14 ◽

2004 ◽

Vol 847 ◽

Author(s):

S.V. Chong ◽

B. Ingham ◽

J.L. Tallon

Keyword(s):

Tungsten Oxide ◽

Sol Gel ◽

Dip Coating ◽

Ammonia Solution ◽

Nitrogen Atmosphere ◽

Tungstic Acid ◽

Hybrid Films ◽

Hybrid Compounds ◽

Synthetic Routes ◽

First Time

ABSTRACTThe syntheses of tungsten oxide-organic amine hybrids via homogenous and heterogeneous routes were explored and compared. In the former case, tungstic acid (H2WO4) and an appropriate amine were dissolved in ammonia solution under nitrogen atmosphere, and the product was precipitated out via evaporation of the solvent. In heterogeneous synthesis, a non-aqueous approach was employed in which H2WO4 powder was aged in a solution consisting of the amine dissolved in an appropriate organic solvent. XRD and FTIR showed that the hybrid materials obtained from the two different methods are identical. Based on these findings, we were able to prepare tungsten oxide hybrid films for the first time, by dip-coating tungstic acid films prepared from sol-gel techniques, in a non-aqueous diamine solution. The XRD spectra of these films exhibit a series of harmonic peaks, indexed as [00k ], which correspond to the Bragg peaks for the hybrid compounds. SEM shows the morphology of tungstic acid changes from the irregularly shaped platelets to a needle-like structure of the hybrids and resulted in a loosely packed coating.

Download Full-text