scholarly journals Influence of Synthesis Method on LTA Time-Dependent Stability

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2122 ◽  
Author(s):  
Claudia Belviso ◽  
Antonio Lettino ◽  
Francesco Cavalcante
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Process ◽  
Synthesis Method ◽  
Synthetic Zeolite ◽  
Time Dependent ◽  
Time Stability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lta Zeolite ◽  
Scanning Electron

Time-stability of LTA zeolite formed by hydrothermal method with or without the action of ultrasonic irradiation was investigated by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The results show that 6 months after the synthesis by hydrothermal process with continuous sonication, LTA evolves into a more stable sodalite, whereas no differences are detected 12 months after LTA synthesis by conventional pre-fused hydrothermal process. These data confirm that using the two approaches, different mechanisms control both zeolite crystallization and time-stability of the newly-formed mineral at solid state. The results are particularly important in the light of the synthetic zeolite application.

SIZE-INDUCED EFFECTS IN NANOSTRUCTURED NiFe2O4

2010 ◽  
Vol 24 (30) ◽  
pp. 5973-5985
Author(s):  
M. GUNES ◽  
H. GENCER ◽  
T. IZGI ◽  
V. S. KOLAT ◽  
S. ATALAY
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Structural Parameters ◽  
Hydrothermal Process ◽  
Lattice Parameter ◽  
Effect Of Temperature ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

NiFe 2 O 4 nanoparticles were successfully prepared by a hydrothermal process, and the effect of temperature on them was studied. The particles were annealed at various temperatures ranging from 413 to 1473 K. Studies were carried out using powder X-ray diffraction, scanning electron microscopy, infrared spectroscopy, differential thermal analysis, thermogravimetric analysis and a vibrating sample magnetometer. The annealing temperature had a significant effect on the magnetic and structural parameters, such as the crystallite size, lattice parameter, magnetization and coercivity.

Blue Upconversion Luminescence Properties of La2(WO4)3:Yb3+/Tm3+Phosphor

2011 ◽  
Vol 399-401 ◽  
pp. 1020-1025
Author(s):  
Jin Sheng Liao ◽  
Hang Ying You ◽  
Qing Xia Wu ◽  
He Rui Wen ◽  
Jing Lin Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Hydrothermal Process ◽  
Pumping Power ◽  
X Ray Diffraction ◽  
X Ray ◽  
Laser Pumping ◽  
Upconversion Mechanism ◽  
Upconversion Emissions ◽  
Scanning Electron

Monoclinic La2(WO4)3 nanophosphors codoped with Tm3+ and Yb3+ ions were synthesized via hydrothermal process followed by heat treatment. Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize as-prepared samples. The dependences of Yb3+/ concentration and laser pumping power on the upconversion emissions were extensively investigated. The results show that upconversion luminescence increases with the Yb3+/ concentration and gets its peak at 30 %. The upconversion mechanism and process in the Yb3+/Tm3+ codoped La2(WO4)3 phosphors were analysed.

Hydrothermal Synthesis and Electrocatalytic Property for H2O2 Reduction of Co3O4 Nanocubes

2011 ◽  
Vol 311-313 ◽  
pp. 477-480
Author(s):  
Zhi Ai Yang ◽  
Li Jin Feng ◽  
Xia Wang ◽  
Rong Ma ◽  
Jian Ping Sun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Process ◽  
Linear Sweep Voltammetry ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
Linear Sweep ◽  
Electrocatalytic Property ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Subscript textThe Co3O4 nanocubes were synthesized by hydrothermal process. The products are characterized in detail by multiform techniques: scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray analysis. The results show that the products are uniform nanocubes with an average crystallite size about 20-40 nm. Electrocatalytic property of the prepared Co3O4 nanocubes was characterized by linear sweep voltammetry. LSV results indicate that Co3O4 nanocubes exhibit a remarkable electrocatalytic activity for the H2O2 reduction.

scholarly journals Synthesis and Catalase Mimic Activity of MnO2 Nano Powder Prepared by Hydrothermal Process

2019 ◽  
Vol 27 (2) ◽  
pp. 228-237 ◽  
Author(s):  
Rashed T. Rasheed ◽  
Sariya D. Al-Algawi ◽  
Rosul M. N.
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Annealing Temperature ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Powder ◽  
Atomic Force ◽  
Different Temperatures ◽  
Scanning Electron

Manganese dioxide (MnO2) nanopowder has been synthesized by hydrothermal method. MnO2 was annealed at different temperatures (250, 400, 550, 700˚C). The crystal structure and surface morphology of these nanostructures were characterized by X-ray diffraction (XRD), Atomic Force Microscope (AFM) and Scanning Electron Microscopy (SEM). The catalase mimic activity (catalytic activity) of MnO2 against hydrogen peroxide (H2O2) was studied by using the new method and found that 400˚C is the best annealing temperature.

scholarly journals Synthesis of Zeolite NaA from Low Grade (High Impurities) Indonesian Natural Zeolite

2014 ◽  
Vol 14 (2) ◽  
pp. 138-142 ◽  
Author(s):  
Asalil Mustain ◽  
Gede Wibawa ◽  
Mukhammad Furoiddun Nais ◽  
Miftakhul Falah
Keyword(s):  
Electron Microscopy ◽  
Natural Zeolite ◽  
Synthesis Method ◽  
Sem Analysis ◽  
Low Grade ◽  
Framework Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zeolite Naa ◽  
Scanning Electron

The zeolite NaA has been successfully synthesized from the low grade natural zeolite with high impurities. The synthesis method was started by mixing natural zeolite powder with NH4Cl aqueous solution in the reactor as pretreatment. The use of pretreatment was to reduce the impurities contents in the zeolite. The process was followed by alkaline fusion hydrothermal treatment to modify the framework structure of natural zeolite and reduce the SiO2/Al2O3 ratio. Finally, the synthesized zeolite was calcined at 600 °C for 2 h. The final zeolite product was characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the morphology of the zeolite NaA was cubic shape as observed by SEM analysis and the synthesized zeolite NaA with pretreatment gave less impurity than without pretreatment.

scholarly journals Interzeolitic Transformation of Clinoptilolite into GIS and LTA Zeolite

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1313
Author(s):  
Renata C. F. de Lima ◽  
Daniele da Silva Oliveira ◽  
Sibele B. C. Pergher
Keyword(s):  
Electron Microscopy ◽  
X Ray Diffraction ◽  
Synthesis Time ◽  
X Ray ◽  
Synthesis Conditions ◽  
Environmentally Sustainable ◽  
Lta Zeolite ◽  
Clinoptilolite Zeolite ◽  
Natural Clinoptilolite ◽  
Scanning Electron

A natural clinoptilolite zeolite was transformed into other zeolites of greater industrial interest, such as zeolites with GIS and LTA structures. The synthesis conditions were studied, and the interzeolitic transformation was characterized by X-ray diffraction (XRD), X-ray fluorescence (FRX), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). From the results, it was possible to observe that the GIS and LTA zeolites were successfully synthesized. Furthermore, the results revealed that a synthesis time of 4 days was enough to obtain the GIS structure, and 4 h was sufficient to obtain LTA. The interzeolitic transformation can be explained by the RBU (Ring Building Unit) approach using C4 units from the HEU topology. The use of clinoptilolite in the synthesis of other zeolites is an innovative, economically viable, and environmentally sustainable process that exploits a material that exists in large quantities and is still little explored by industry.

scholarly journals Effects of different Sn contents on formation of Ti2SnC by self-propagating high-temperature synthesis method in Ti-Sn-C and Ti-Sn-C-TiC systems

2014 ◽  
Vol 32 (4) ◽  
pp. 696-701 ◽  
Author(s):  
Hong-Yan Sun ◽  
Xin Kong ◽  
Wei Sen ◽  
Zhong-Zhou Yi ◽  
Bao-Sen Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Raw Materials ◽  
Synthesis Method ◽  
Combustion Products ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Temperature Synthesis ◽  
X Ray ◽  
High Temperature Synthesis ◽  
Scanning Electron

AbstractEffect of different Sn contents on combustion synthesis of Ti2SnC was studied using elemental Ti, Sn, C and TiC powders as raw materials in the Ti-Sn-C and Ti-Sn-C-TiC system, in which the molar ratio of Ti/C was set as 2:1. The reaction mechanism for the formation of Ti2SnC was also investigated. The results showed that the amount of Ti2SnC in combustion products firstly increased with increasing of Sn content (0.6 to 0.8 mol), and then decreased with further increasing of Sn content (1.0 to 1.2 mol). Upon addition of 15 % TiC instead of Ti and C, the optimum addition of Sn decreased to 0.7 mol and a higher purity of Ti2SnC was obtained. The Ti2SnC powders were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD).

Hydrothermal Synthesis of 3D Flower-Like Bismuth Trisulphide Microcrystallines

2013 ◽  
Vol 634-638 ◽  
pp. 2207-2210 ◽  
Author(s):  
Pin Jiang Li ◽  
Yan Ge Zhang ◽  
Bao Jun Huang ◽  
Chen Yu ◽  
Ling Zhuge ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Synthesis ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
Structure Directing Agent ◽  
X Ray ◽  
Laser Raman ◽  
One Step ◽  
Scanning Electron

3D flower-like bismuth trisulphide microcrystallines has been successfully prepared via one step hydrothermal process and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and laser Raman spectrometer techniques. The morphologies of the Bi2S3 microcrystallines were influenced by the surfactant Na2(EDTA), which acts as a structure directing agent.

Polymorphological LaVO 4:Dy 3+ Phosphors: Hydrothermal Synthesis and Luminescent Properties

2011 ◽  
Vol 239-242 ◽  
pp. 1735-1738
Author(s):  
Guo Cong Liu ◽  
Ke Long Huang
Keyword(s):  
Electron Microscopy ◽  
Morphological Evolution ◽  
Hydrothermal Process ◽  
Luminescent Properties ◽  
Growth Mechanisms ◽  
X Ray Diffraction ◽  
Rod Bundles ◽  
X Ray ◽  
Rod Bundle ◽  
Scanning Electron

Tetragonal LaVO4:Dy3+ crystals with novel shapes of rod, rod-bundles and needle-like flower were successfully synthesized via a facile and surfactant-free hydrothermal process. The products were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence spectroscopy (PL).The experimental results showed that the concentration of the precursor and the reaction temperature played important roles in morphological evolution of LaVO4:Dy3+ crystals (NCs). It was found that needle-like flower LaVO4:Dy3+ exhibited the highest B/Y value compared with rod and rod-bundle samples. Possible growth mechanisms of polymorphological LaVO4:Dy3+ crystals were briefly discussed.

Study of the Formation of WOx Nanostructures Supported on Zirconia Prepared by Different Synthesis Routes

2010 ◽  
Vol 1279 ◽  
Author(s):  
Martha L. Hernández ◽  
Ascención Montoya ◽  
Paz Del angel ◽  
Silvia P. Paredes ◽  
Sergio O. Flores
Keyword(s):  
Electron Microscopy ◽  
Active Sites ◽  
Synthesis Method ◽  
Isomerization Reaction ◽  
X Ray Diffraction ◽  
Tungstated Zirconia ◽  
X Ray ◽  
Preparation Route ◽  
Synthesis Routes ◽  
Scanning Electron

AbstractDifferent synthesis procedures of Pt supported on tungstated zirconia catalysts (Pt/WOx-ZrO2) were investigated with the aim to elucidate the different WOx nanostructures developed on the zirconia surface depending on the preparation route. Pt/WOx-ZrO2 catalysts were synthesized by the coprecipitation and impregnation methods and pretreated by various procedures such as different calcinations temperatures or the use of reflux. The catalysts characterization was carried out by X-ray diffraction (XRD), Raman spectroscopy, transmission and scanning electron microscopy (TEM, SEM) and nitrogen physisorption, and the catalytic activity was evaluated in the n-hexane isomerization reaction. The results indicate that the development of active sites for isomerization of n-hexane is enhanced by the stabilization of the WOx nanostructures on the surface of zirconia, before the formation of the WO3 crystallites, and it largely depends on the synthesis method.

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