Direct Conversion of TiO2 Sol to Nanocrystalline Anatase at 85 °C

2002 ◽  
Vol 17 (6) ◽  
pp. 1507-1512 ◽  
Author(s):  
K. I. Gnanasekar ◽  
V. Subramanian ◽  
J. Robinson ◽  
K. I. Gnanasekar ◽  
K. I. Gnanasekar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fine Particles ◽  
Anatase Phase ◽  
Direct Conversion ◽  
Scanning Calorimetry ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Tio2 Sol ◽  
Diffraction Patterns

Nanocrystalline TiO2 anatase with particle size in the range of 5–7 nm has been prepared by in situ cracking of the sol at 85 °C, thereby avoiding the intermediate gel formation process. Hydrolysis of Ti(O-isoPr)4 was carried out in excess of 2-propanol to keep the suspension of fine particles from agglomeration. Differential thermal analysis, thermogravimetric analysis, differential scanning calorimetry, powder x-ray diffraction (XRD), and electron microscopy have been used to characterize the samples. Gel to crystalline conversion, which requires a temperature of at least 400 °C, can be achieved by digesting the TiO2 sol at 85 °C. XRD and selected area electron diffraction patterns show the presence of a small amount of brookite phase along with the major anatase phase. High-resolution transmission electron microscopy shows that the average grain size of TiO2 particle remains around 5–9 nm even when heated at 510 °C.

scholarly journals Nano-Scale Rare Earth Distribution in Fly Ash Derived from the Combustion of the Fire Clay Coal, Kentucky

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 206 ◽  
Author(s):  
James Hower ◽  
Dali Qian ◽  
Nicolas Briot ◽  
Eduardo Santillan-Jimenez ◽  
Madison Hood ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Fly Ash ◽  
Electron Diffraction ◽  
Eastern Kentucky ◽  
Nano Scale ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Fire Clay

Fly ash from the combustion of eastern Kentucky Fire Clay coal in a southeastern United States pulverized-coal power plant was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). TEM combined with elemental analysis via energy dispersive X-ray spectroscopy (EDS) showed that rare earth elements (REE; specifically, La, Ce, Nd, Pr, and Sm) were distributed within glassy particles. In certain cases, the REE were accompanied by phosphorous, suggesting a monazite or similar mineral form. However, the electron diffraction patterns of apparent phosphate minerals were not definitive, and P-lean regions of the glass consisted of amorphous phases. Therefore, the distribution of the REE in the fly ash seemed to be in the form of TEM-visible nano-scale crystalline minerals, with additional distributions corresponding to overlapping ultra-fine minerals and even true atomic dispersion within the fly ash glass.

Novel synthesis and characterization of nanocrystalline thoria from oxalate precursor via reverse micellar route

2013 ◽  
Vol 101 (1) ◽  
pp. 7-12 ◽  
Author(s):  
R. Gupta ◽  
S. K. Gupta ◽  
S. K. Aggarwal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ammonium Oxalate ◽  
Thorium Nitrate ◽  
Oxalate Precursor ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Thorium Oxalate

Abstract Nanoparticles of thorium oxalate were synthesized by the reaction of thorium nitrate and ammonium oxalate by the microemulsion method. The Th02 nanoparticles were obtained by heating thorium oxalate nanoparticles at 500 °C in air. The oxalate and oxide nanoparticles of thorium were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and selected area electron diffraction (SAED). X-ray diffraction studies showed the mono-phasic nature of the powder thoria. The particle size was obtained from X-ray line broadening (~l0 nm) and transmission electron microscopy (~l0 nm). Dynamic light scattering (DLS) was used to calculate the average grain size of the particles. SAED confirmed the nanocrystalline nature of thoria particles. High resolution transmission electron microscopy (HRTEM) was also carried out to understand the morphology of the system. The monodisperse nanoparticles of thoria are promising for future reactor technologies.

Fabrication and Characterization of Nanostructured Surface Layer of 38CrSi Steel

2007 ◽  
Author(s):  
Shi-Ning Ma ◽  
De-Ma Ba ◽  
Chang-Qing Li ◽  
Fan-Jun Meng
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Surface Layer ◽  
Grain Refinement ◽  
Fine Particles ◽  
Nanostructured Surface ◽  
Cell Structures ◽  
Strain And Strain Rate ◽  
Transmission Electron ◽  
Average Grain Size

A nanocrystalline surface layer was fabricated on a 38CrSi Steel with tempered sorbite structure by using Supersonic Fine Particles Bombarding (SFPB). The microstructural evolution of SFPB-treated specimens under different processing conditions was characterized by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Experimental evidence showed severe plastic deformation and obvious grains refinement were observed and a nanocrystalline surface layer (grain size < 100nm) was found after SFPB treatment. The thickness of nanostructured surface layer varies from a few to about 25μm as treated time increasing from 80s to 240s, but the grain size varies slightly. For the sample treated for 240s, the average grain size of equiaxed nanocrystallites with random crystallographic orientations on the top surface layer is about 16nm. The indexing of diffraction rings indicates nanostructured surface layer consists of ferrite and cementite phases without any evidence of a new phase. The structure size increases gradually from nano-scale to original-scale with an increase of the distance from the top surface layer. In the region about 20–30μm deep from the top surface, the microstructures are mainly composed of 60–100nm roughly equiaxed grains and subgrains. Some subbounsaries are composed of dense dislocation walls (DDWs). In this regime some cell structures are also seen, which are separated by dislocation lines (DTs) and some DDWs. Experimental analysis indicate coarse-grains are gradually refined into nano-sized grains by dislocations activity with gradual increase of strain and strain rate from matrix to treated surface. Both ferrite and cementite phases occur grain refinement. Grain refinement of 38CrSi sample is mainly attributed to the movement of dislocation.

scholarly journals PHASE-TRANSFORMATION DYNAMICS AND CHARACTERIZATION OF PRECIPITATES IN THE Cu-3Ti-3Ni-0.5Si ALLOY

2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Jia Liu ◽  
Jituo Liu ◽  
Xianhui Wang ◽  
Chong Fu ◽  
Yanlong Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Phase Transformation ◽  
Volume Fraction ◽  
Formation Enthalpy ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Diffraction Patterns ◽  
Precipitated Phases

In this paper we investigated the phase-transformation dynamics of the Cu-3Ti-3Ni-0.5Si alloy by applying the Avrami method to phase-transformation dynamics and electrical conductivity based on the relationship between the electrical conductivity and the volume fraction of precipitates in the Cu-3Ti-3Ni-0.5Si alloy. The results corroborated well with the experimental data. The microstructure and precipitated phases were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The analysis of the selected-area electron-diffraction patterns indicated that the precipitates formed in the matrix of the Cu-3Ti-3Ni-0.5Si alloy during aging, correspond to the Ni3Ti, Ni3Si, and Ni2Si phases. According to the values of formation enthalpy and cohesive energy determined by first-principle calculations, the formation of the Ni2Si phase is more favorable compared to the Ni3Si and Ni3Ti phases, and the Ni3Ti exhibits improved structural stability compared to the Ni2Si and Ni3Si phases.

Interfacial Reaction in Aluminum/Carbon Multilayer Thin Films

1997 ◽  
Vol 481 ◽  
Author(s):  
K. Landry ◽  
H. Sieber ◽  
M. Sui ◽  
J. H. Perepezko
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Second Step ◽  
Multilayer Thin Films ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Modulation Wavelength

ABSTRACTThe reaction at the interface between Al and amorphous C in Al/C multilayer thin films with modulation wavelengths of about 25nm and 125nm has been investigated by differential scanning calorimetry, X-ray diffraction, transmission electron microscopy/selected area electron diffraction and high resolution transmission electron microscopy. The reaction was found to take place in two steps. The first step onsets at about 300°C, and was identified as the diffusion of C into Al. The second step starts above 400°C, at a temperature strongly dependent on the modulation wavelength of the film, and is the formation of A14C3. The carbide has been observed to nucleate and grow inside the Al layers. The multilayer structure is preserved in the samples up to at least 550°C, and Al grains start to grow at or below 300°C.

Facile Enrichment and Photocatalytical Degradation of Low Concentration MB in Aqueous Solution

2011 ◽  
Vol 110-116 ◽  
pp. 2308-2315
Author(s):  
Liu Xue Zhang ◽  
Xiu Lian Wang
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Fine Particles ◽  
X Ray Diffraction ◽  
High Concentration ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Low Concentrations ◽  
Hydrolysis Of

Fine particles of photoactive anatase-type TiO2, prepared by hydrolysis of tetrabutyl orthotitanate and crystallized under microwave (MV) irradiation, were loaded on adsorbent support attapulgite (ATP). The prepared hybrids TiO2-ATP were characterized with transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and X-ray diffraction (XRD) and photoactivity properties were evaluated separately. The substrates of target were adsorbed on the adsorbent support, and then a high concentration environments of the substrate was formed around the loaded TiO2, resulting in an increase in the photodestruction rate. One of the most interesting features of the resulting catalysts with low titania contain (<30%) is their fast decantability in comparison with that of TiO2. This way one of the most important drawbacks of photocatalysis, the catalysts separation from the solution, was overcome by simple sedimentation and decantation. The low concentrations MB may be removed through enrichment and photodegradation using the prepared TiO2-ATP photocatalyst.

Template-Assisted Fabrication of Double-Shelled Nanotubes Composed of Inner Shell Pb(Zr0.52Ti0.48)O3 and Outer Shell TiO2 by Sol-Gel Process with Spin-Coating Technique

2011 ◽  
Vol 1292 ◽  
Author(s):  
Y. C. Choi ◽  
S. Y. Cho ◽  
S. D. Bu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Spin Coating ◽  
Sol Gel ◽  
Outer Shell ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Scanning Transmission ◽  
Diffraction Patterns

ABSTRACTDouble-shelled nanotubes composed of inner shell Pb(Zr0.52Ti0.48)O3 (PZT) and outer shell TiO2 are successfully fabricated by a spin coating of each sol-gel solution on porous anodic alumina template. Field emission transmission electron microscopy images show that they have a ~ 10 nm wall thickness. The selected area electron diffraction patterns show that they have two mixed crystalline phases of tetragonal PZT and anatase TiO2. The analyses of scanning transmission electron microscopy equipped with energy dispersive X-ray spectroscopy confirm their uniform distribution of each element.

Structure and Microwave Dielectric Properties of Ca1−xYxTi1−xAlxO3 (CYTA) Ceramics

2005 ◽  
Vol 20 (9) ◽  
pp. 2391-2399 ◽  
Author(s):  
Antonio Feteira ◽  
Derek C. Sinclair ◽  
Michael T. Lanagan
Keyword(s):  
Electron Microscopy ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric ◽  
Transmission Electron ◽  
Complete Solid Solution ◽  
Average Grain Size ◽  
Incomplete Reaction ◽  
Diffraction Patterns ◽  
Ferroelastic Domains

The structure and dielectric properties of Ca1−xYxTi1−xAlxO3 (CYTA) ceramics prepared by the mixed-oxide route have been investigated. CYTA forms a complete solid solution with an orthorhombic perovskite structure. Residual Y4Al2O9 and Y3Al5O12 resulting from incomplete reaction are observed for ⩾ 0.9. Scanning electron microscopy shows that CYTA ceramics exhibit uniform microstructures, with an average grain size that decreases from ∼200 μm at x = 0 to ∼10 μm at x = 1.0. Transmission electron microscopy of CYTA (x = 0.3) ceramics reveals the presence of ferroelastic domains, and electron-diffraction patterns are indexed on the Pnma space group, consistent with an a+b−b− octahedral tilted structure. The relative permittivity, ϵr, decreases continuously from 170 to 12, while the microwave quality factor, Q·fr, increases from 10,000 to 12,000 GHz, for x = 0 and 1, respectively. CYTA (x = 0.30) ceramics exhibit ϵr ∼ 38, Q·fr of ∼14,212 GHz, and a temperature coefficient of resonance frequency, τf, of −14 ppm/°C. Small additions of acceptor (0.3 wt% ZnO) or donor (1 wt% Nb2O5) dopants decrease Q·fr by ∼20–30%, respectively.

scholarly journals Preparation of Biomorphic Porous SiC Ceramics from Bamboo by Combining Sol–Gel Impregnation and Carbothermal Reduction

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1442 ◽  
Author(s):  
Hung ◽  
Wu ◽  
Xu ◽  
Wu
Keyword(s):  
Electron Microscopy ◽  
Carbothermal Reduction ◽  
Sol Gel ◽  
Atomic Plane ◽  
Growth Direction ◽  
X Ray Diffraction ◽  
Selected Area Electron Diffraction ◽  
Sic Ceramics ◽  
Transmission Electron ◽  
Diffraction Patterns

This study investigated the feasibility of using bamboo to prepare biomorphic porous silicon carbide (bio-SiC) ceramics through a combination of sol–gel impregnation and carbothermal reduction. The effects of sintering temperature, sintering duration, and sol–gel impregnation cycles on the crystalline phases and microstructure of bio-SiC were investigated. X-ray diffraction patterns revealed that when bamboo charcoal–SiO2 composites (BcSiCs) were sintered at 1700 °C for more than 2 h, the resulting bio-SiC ceramics exhibited significant β-SiC diffraction peaks. In addition, when the composites were sintered at 1700 °C for 2 h, scanning electron microscopy micrographs of the resulting bio-SiC ceramic prepared using a single impregnation cycle showed the presence of SiC crystalline particles and nanowires in the cell wall and cell lumen of the carbon template, respectively. However, bio-SiC prepared using three and five repeated cycles of sol–gel impregnation exhibited a foam-like microstructure compared with that prepared using a single impregnation cycle. Moreover, high-resolution transmission electron microscopy and selected area electron diffraction revealed that the atomic plane of the nanowire of bio-SiC prepared from BcSiCs had a planar distance of 0.25 nm and was perpendicular to the (111) growth direction. Similar results were observed for the bio-SiC ceramics prepared from bamboo–SiO2 composites (BSiCs). Accordingly, bio-SiC ceramics can be directly and successfully prepared from BSiCs, simplifying the manufacturing process of SiC ceramics.

scholarly journals Luteolin-Fabricated ZnO Nanostructures Showed PLK-1 Mediated Anti-Breast Cancer Activity

Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 385
Author(s):  
Shiva Prasad Kollur ◽  
Shashanka K. Prasad ◽  
Sushma Pradeep ◽  
Ravindra Veerapur ◽  
Sharanagouda S. Patil ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cancer Cell Line ◽  
Sem Images ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Lattice Planes ◽  
Cancer Activity

The present work describes a facile and convenient procedure for synthesizing zinc oxide nanoparticles using luteolin isolated from Eclipta alba plant (L-ZnONPs) at room temperature. The formation of as-grown L-ZnONPs was confirmed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and selected area electron diffraction (SAED). The Wurtzite structure of ZnO was observed by its hexagonal phases in diffraction patterns. The SEM images revealed the different sizes and morphologies of L-ZnONPs, with diameters between 12 and 25 nm. The HR-TEM result showed that the inter-planar distance between two lattice fringes was 0.262 nm, which coincides with the d-spacing of (002) and (101) lattice planes of the as-obtained material. The anticancer activity of L-ZnONPs against the breast cancer cell line MCF-7 was greater as compared to that of luteolin or ZnO alone. The mechanistic evaluation of such an activity carried out using in silico methods suggested that the anti-breast cancer activity of L-ZnONPs was mediated by polo-like kinase 1 (PLK1) proteins.

Sign in / Sign up

Export Citation Format

Share Document