scholarly journals Low-Temperature Synthesis and Thermodynamic and Electrical Properties of Barium Titanate Nanorods

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
Florentina Maxim ◽  
Daniela Berger ◽  
Florina Teodorescu ◽  
Cristian Hornoiu ◽  
Cecilia Lete ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Barium Titanate ◽  
Perovskite Phase ◽  
Functional Materials ◽  
Building Blocks ◽  
Titanium Isopropoxide ◽  
Oriented Attachment ◽  
Equilibrium Partial Pressure ◽  
Hydrothermal Route ◽  
Lower Oxygen

Studies regarding the morphology dependence of the perovskite-type oxides functional materials properties are of recent interest. With this aim, nanorods (NRs) and nanocubes (NCs) of barium titanate (BaTiO3) have been successfully synthesized via a hydrothermal route at temperature as low as 408 K, employing barium acetate, titanium isopropoxide, and sodium hydroxide as reagents without any surfactant or template. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray powder diffraction (XRD), used for the morphology and structure analyses, showed that the NRs were formed by an oriented attachment of the NCs building-blocks with 20 nm average crystallites size. The thermodynamic properties represented by the relative partial molar free energies, enthalpies, and entropies of the oxygen dissolution in the perovskite phase, as well as the equilibrium partial pressure of oxygen, indicated that NRs powders have lower oxygen vacancies concentration than the NCs. This NRs characteristic, together with higher tetragonallity of the structure, leads to the enhancement of the dielectric properties of BaTiO3ceramics. The results presented in this work show indubitably the importance of the nanopowders morphology on the material properties.

Photocatalytic Degradation of 2-chlorophenol over TiO2 Powder

2014 ◽  
Vol 931-932 ◽  
pp. 291-295
Author(s):  
Pusit Pookmanee ◽  
Songpon Ngamta ◽  
Wiyong Kangwansupamonkon ◽  
Ratchadaporn Puntharod ◽  
Supaporn Sangsrichan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Photocatalytic Degradation ◽  
Ph Value ◽  
Ammonium Hydroxide ◽  
Titanium Isopropoxide ◽  
Chemical Compositions ◽  
Mixed Solution ◽  
Hydrothermal Route ◽  
Scanning Electron

Titanium dioxide (TiO2) powder was prepared by hydrothermal route. Titanium isopropoxide, ammonium hydroxide and nitric acid were used as the starting materials. The final pH value of mixed solution was 1 and treated at 80 and 100 °C for 26h. The phase transition of TiO2powder was studied by Xray diffraction (XRD). Multiphase of anatase and rutile of TiO2powder were obtained at 80 and 100 °C for 26h without calcination steps. The morphology of TiO2powder was investigated by scanning electron microscopy (SEM). The particle was highly agglomerated and irregular in shape with the range of particle size of 0.10.3 μm. The chemical composition of TiO2powder was examined by energy dispersive spectroscopy (EDS). The element chemical compositions show the characteristic Xray energy level as follows: titanium Kα= 4.51 keV and Kβ= 4.93 keV and oxygen Kα= 0.52 keV, respectively. The photocatalytic degradation efficiency of 2chlorophenol (2CP) over TiO2powder was determined by gas chromatography (GC). It was found that TiO2powder prepared by hydrothermal route at 80 °C for 2h was the best efficiency for photocatalytic degradation of 2CP.

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

scholarly journals Towards Iron-Titanium Oxide Nanostructures from Ecuadorian Black Mineral Sands

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 122
Author(s):  
Karina J. Lagos ◽  
Bojan A. Marinkovic ◽  
Alexis Debut ◽  
Karla Vizuete ◽  
Víctor H. Guerrero ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Titanium Oxide ◽  
Low Cost ◽  
Mineral Resources ◽  
Added Value ◽  
Secondary Phases ◽  
Hydrothermal Route ◽  
Oxide Nanostructures ◽  
Transmission Electron ◽  
Pre Treatment

Ecuadorian black mineral sands were used as starting material for the production of iron-titanium oxide nanostructures. For this purpose, two types of mineral processing were carried out, one incorporating a pre-treatment before conducting an alkaline hydrothermal synthesis (NaOH 10 M at 180 °C for 72 h), and the other prescinding this first step. Nanosheet-assembled flowers and nanoparticle agglomerates were obtained from the procedure including the pre-treatment. Conversely, nanobelts and plate-like particles were prepared by the single hydrothermal route. The nanoscale features of the product morphologies were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. The ilmenite and hematite molar fractions, within the ilmenite-hematite solid solution, in the as-synthetized samples were estimated by Brown’s approach using the computed values of unit-cell volumes from Le Bail adjustments of X-ray powder diffraction (XRPD) patterns. The resulting materials were mainly composed of Fe-rich ilmenite-hematite solid solutions (hematite molar contents ≥0.6). Secondary phases, which possibly belong to lepidocrocite-like or corrugated titanate structures, were also identified. The current study demonstrated the feasibility of employing Ecuadorian mineral resources as low-cost precursors to synthesize high-added-value nanostructures with promising applications in several fields.

scholarly journals Core-Substituted Naphthalene-diimides (cNDI) and Related Derivatives: Versatile Scaffold for Supramolecular Assembly and Functional Materials

2021 ◽  
Author(s):  
Anurag Mukherjee ◽  
Suhrit Ghosh
Keyword(s):  
Photophysical Properties ◽  
Supramolecular Assembly ◽  
Functional Materials ◽  
Building Blocks ◽  
Short Review ◽  
Molecular Engineering ◽  
Organic Optoelectronics ◽  
Naphthalene Diimide ◽  
Naphthalene Diimides ◽  
Derivatives Of

Naphthalene-diimide (NDI) derived building blocks have been explored extensively for supramolecular assembly as they exhibit attractive photophysical properties, suitable for applications in organic optoelectronics. Core-substituted derivatives of the NDI chromophore (cNDI) differ significantly from the parent NDI dye in terms of optical and redox properties. Adequate molecular engineering opportunities and substitution-dependent tunable optoelectronic properties make cNDI derivatives highly promising candidates for supramolecular assembly and functional material. This short review discusses recent development in the area of functional supramolecular assemblies based on cNDIs and related molecules.

scholarly journals Amyloid fibril-directed synthesis of silica core–shell nanofilaments, gels, and aerogels

2019 ◽  
Vol 116 (10) ◽  
pp. 4012-4017 ◽  
Author(s):  
Yiping Cao ◽  
Sreenath Bolisetty ◽  
Gianna Wolfisberg ◽  
Jozef Adamcik ◽  
Raffaele Mezzenga
Keyword(s):  
Amyloid Fibril ◽  
Functional Materials ◽  
Building Blocks ◽  
Inorganic Materials ◽  
Core Shell ◽  
Shear Stresses ◽  
Bending Rigidity ◽  
Widespread Application ◽  
Nonmonotonic Dependence ◽  
Silica Core

Amyloid fibrils have evolved from purely pathological materials implicated in neurodegenerative diseases to efficient templates for last-generation functional materials and nanotechnologies. Due to their high intrinsic stiffness and extreme aspect ratio, amyloid fibril hydrogels can serve as ideal building blocks for material design and synthesis. Yet, in these gels, stiffness is generally not paired by toughness, and their fragile nature hinders significantly their widespread application. Here we introduce an amyloid-assisted biosilicification process, which leads to the formation of silicified nanofibrils (fibril–silica core–shell nanofilaments) with stiffness up to and beyond ∼20 GPa, approaching the Young’s moduli of many metal alloys and inorganic materials. The silica shell endows the silicified fibrils with large bending rigidity, reflected in hydrogels with elasticity three orders of magnitude beyond conventional amyloid fibril hydrogels. A constitutive theoretical model is proposed that, despite its simplicity, quantitatively interprets the nonmonotonic dependence of the gel elasticity upon the filaments bundling promoted by shear stresses. The application of these hybrid silica–amyloid hydrogels is demonstrated on the fabrication of mechanically stable aerogels generated via sequential solvent exchange, supercriticalCO2removal, and calcination of the amyloid core, leading to aerogels of specific surface area as high as 993m2/g, among the highest values ever reported for aerogels. We finally show that the scope of amyloid hydrogels can be expanded considerably by generating double networks of amyloid and hydrophilic polymers, which combine excellent stiffness and toughness beyond those of each of the constitutive individual networks.

scholarly journals Assessment of SnFe2O4 Nanoparticles for Potential Application in Theranostics: Synthesis, Characterization, In Vitro, and In Vivo Toxicity

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 825
Author(s):  
Saman Sargazi ◽  
Mohammad Reza Hajinezhad ◽  
Abbas Rahdar ◽  
Muhammad Nadeem Zafar ◽  
Aneesa Awan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
A549 Cells ◽  
In Vitro Cytotoxicity ◽  
Hek293 Cells ◽  
Hydrothermal Route ◽  
X Ray ◽  
Tin Chloride ◽  
Bet Analysis

In this research, tin ferrite (SnFe2O4) NPs were synthesized via hydrothermal route using ferric chloride and tin chloride as precursors and were then characterized in terms of morphology and structure using Fourier-transform infrared spectroscopy (FTIR), Ultraviolet–visible spectroscopy (UV-Vis), X-ray power diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and Brunauer–Emmett–Teller (BET) method. The obtained UV-Vis spectra was used to measure band gap energy of as-prepared SnFe2O4 NPs. XRD confirmed the spinel structure of NPs, while SEM and TEM analyses disclosed the size of NPs in the range of 15–50 nm and revealed the spherical shape of NPs. Moreover, energy dispersive X-ray spectroscopy (EDS) and BET analysis was carried out to estimate elemental composition and specific surface area, respectively. In vitro cytotoxicity of the synthesized NPs were studied on normal (HUVEC, HEK293) and cancerous (A549) human cell lines. HUVEC cells were resistant to SnFe2O4 NPs; while a significant decrease in the viability of HEK293 cells was observed when treated with higher concentrations of SnFe2O4 NPs. Furthermore, SnFe2O4 NPs induced dramatic cytotoxicity against A549 cells. For in vivo study, rats received SnFe2O4 NPs at dosages of 0, 0.1, 1, and 10 mg/kg. The 10 mg/kg dose increased serum blood urea nitrogen and creatinine compared to the controls (P < 0.05). The pathology showed necrosis in the liver, heart, and lungs, and the greatest damages were related to the kidneys. Overall, the in vivo and in vitro experiments showed that SnFe2O4 NPs at high doses had toxic effects on lung, liver and kidney cells without inducing toxicity to HUVECs. Further studies are warranted to fully elucidate the side effects of SnFe2O4 NPs for their application in theranostics.

scholarly journals Cross-Linking Effects Dictate the Preference of Galectins to Bind LacNAc-Decorated HPMA Copolymers

2021 ◽  
Vol 22 (11) ◽  
pp. 6000
Author(s):  
Sara Bertuzzi ◽  
Ana Gimeno ◽  
Ane Martinez-Castillo ◽  
Marta G. Lete ◽  
Sandra Delgado ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lectin Binding ◽  
Building Blocks ◽  
Cryo Electron Microscopy ◽  
Hpma Copolymers ◽  
Hydroxypropyl Methacrylamide ◽  
Galectin 3 ◽  
Nmr Methods ◽  
The Individual ◽  
Statistical Effects

The interaction of multi-LacNAc (Galβ1-4GlcNAc)-containing N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers with human galectin-1 (Gal-1) and the carbohydrate recognition domain (CRD) of human galectin-3 (Gal-3) was analyzed using NMR methods in addition to cryo-electron-microscopy and dynamic light scattering (DLS) experiments. The interaction with individual LacNAc-containing components of the polymer was studied for comparison purposes. For Gal-3 CRD, the NMR data suggest a canonical interaction of the individual small-molecule bi- and trivalent ligands with the lectin binding site and better affinity for the trivalent arrangement due to statistical effects. For the glycopolymers, the interaction was stronger, although no evidence for forming a large supramolecule was obtained. In contrast, for Gal-1, the results indicate the formation of large cross-linked supramolecules in the presence of multivalent LacNAc entities for both the individual building blocks and the polymers. Interestingly, the bivalent and trivalent presentation of LacNAc in the polymer did not produce such an increase, indicating that the multivalency provided by the polymer is sufficient for triggering an efficient binding between the glycopolymer and Gal-1. This hypothesis was further demonstrated by electron microscopy and DLS methods.

Effect of hydrothermal dwell time on the diameter-controlled synthesis and magnetic property of MnO2 nanorods

2014 ◽  
Vol 28 (06) ◽  
pp. 1450045 ◽  
Author(s):  
Arbab Mohammad Toufiq ◽  
Fengping Wang ◽  
Qurat-ul-Ain Javed ◽  
Yan Li
Keyword(s):  
Electron Microscopy ◽  
Reaction Time ◽  
Dwell Time ◽  
Hydrothermal Reaction ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
Transmission Electron ◽  
Facile Hydrothermal Route ◽  
Hydrothermal Reaction Time

In this paper, single crystalline 1D tetragonal MnO 2 pen-type nanorods were synthesized by varying the dwell time through a facile hydrothermal route at a reaction temperature of 250°C. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies showed that the diameter of MnO 2 nanorods decreases from 460 nm to 250 nm with the increase in hydrothermal reaction time from 5 h to 15 h. Field-emission scanning electron microscopy (FESEM) and TEM studies revealed the evolution of improved surface morphology of MnO 2 nanorods that are prepared with longer hydrothermal reaction time. The magnetic properties of the products were evaluated using vibrating sample magnetometer (VSM) at room temperature, which showed that the as-prepared samples exhibit weak ferromagnetic behavior. The effect of diameter on the magnetization values was observed and discussed in detail.

scholarly journals Eu2+ and Eu3+ Doubly Doped ZnWO4 Nanoplates with Superior Photocatalytic Performance for Dye Degradation

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 765 ◽  
Author(s):  
Yuan Huang ◽  
Ming Li ◽  
Long Yang ◽  
Bao-gai Zhai
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Performance ◽  
Dye Degradation ◽  
Ammonium Bromide ◽  
Defect Engineering ◽  
Hydrothermal Route ◽  
Crystal Facet ◽  
X Ray ◽  
Cooperative Effects ◽  
Photoluminescence Lifetime

Eu2+ and Eu3+ doubly doped ZnWO4 nanoplates with highly exposed {100} facets were synthesized via a facile hydrothermal route in the presence of surfactant cetyltrimethyl ammonium bromide. These ZnWO4 nanoplates were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectrometry, diffuse UV-vis reflectance spectroscopy, photoluminescence spectrophotometry, and photoluminescence lifetime spectroscopy to determine their morphological, structural, chemical, and optical characteristics. It is found that Eu-doped ZnWO4 nanoplates exhibit superior photo-oxidative capability to completely mineralize the methyl orange into CO2 and H2O, whereas undoped ZnWO4 nanoparticles can only cleave the organic molecules into fragments. The superior photocatalytic performance of Eu-doped ZnWO4 nanoplates can be attributed to the cooperative effects of crystal facet engineering and defect engineering. This is a valuable report on crystal facet engineering in combination with defect engineering for the development of highly efficient photocatalysts.

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