Vapor-Phase Synthesis and Magnetoresistance of (Cd0.993Zn0.007)3As2 Single Crystals

In this article the synthesis, characterization and catalytic activity studies of zirconia based base catalysts such as Mg(II)/ZrO2, Ca(II)/ZrO2 and Ba(II)/ZrO2 coated on honeycomb monoliths is reported. Honeycomb monoliths were coated with Mg(II)/ZrO2, Ca(II)/ZrO2, Ba(II)/ZrO2 and characterized for their physico-chemical properties such as surface basicity, crystallinity and morphology by using relevant techniques. The catalytic activity of these catalytic materials was evaluated in vapor phase synthesis of glycerol carbonate. The reaction conditions were optimized by varying reaction parameters such as nature of catalytic material, molar ratio of the reactants, catalyst bed temperature, feed-rate of the reactants and time-on-stream to obtain highest possible yield of glycerol carbonate with greater selectivity. The catalytic materials were found to be highly efficient in the synthesis of glycerol carbonate with a possible highest yield up to ~98%. These catalytic materials can be easily reactivated and reused in this reaction.Bangladesh J. Sci. Ind. Res.53(1), 21-28, 2018

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Tuning Pt-CeO2 interactions by high-temperature vapor-phase synthesis for improved reducibility of lattice oxygen

Nature Communications ◽

10.1038/s41467-019-09308-5 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 64

Author(s):

Xavier Isidro Pereira-Hernández ◽

Andrew DeLaRiva ◽

Valery Muravev ◽

Deepak Kunwar ◽

Haifeng Xiong ◽

...

Keyword(s):

High Temperature ◽

Co Oxidation ◽

Vapor Phase ◽

Ambient Pressure ◽

Lattice Oxygen ◽

Single Atom ◽

Stable Form ◽

Phase Synthesis ◽

Vapor Phase Synthesis ◽

High Temperature Vapor

Abstract In this work, we compare the CO oxidation performance of Pt single atom catalysts (SACs) prepared via two methods: (1) conventional wet chemical synthesis (strong electrostatic adsorption–SEA) with calcination at 350 °C in air; and (2) high temperature vapor phase synthesis (atom trapping–AT) with calcination in air at 800 °C leading to ionic Pt being trapped on the CeO2 in a thermally stable form. As-synthesized, both SACs are inactive for low temperature (<150 °C) CO oxidation. After treatment in CO at 275 °C, both catalysts show enhanced reactivity. Despite similar Pt metal particle size, the AT catalyst is significantly more active, with onset of CO oxidation near room temperature. A combination of near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) and CO temperature-programmed reduction (CO-TPR) shows that the high reactivity at low temperatures can be related to the improved reducibility of lattice oxygen on the CeO2 support.

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Gas-phase synthesis of single crystals of Ge–Si system

International Journal of Modern Physics B ◽

10.1142/s0217979220501787 ◽

2020 ◽

Vol 34 (19) ◽

pp. 2050178

Author(s):

Aynur I. Hashimova

Keyword(s):

Temperature Gradient ◽

Single Crystals ◽

Gas Phase ◽

Vapor Phase ◽

Solid Solutions ◽

Closed Volume ◽

Phase Synthesis ◽

Polycrystalline Layer ◽

Cold Zone ◽

Hot Zone

In this study, the synthesis of single crystals of solid solutions Ge[Formula: see text]Si[Formula: see text] from the gas phase was performed in two different variants. Here, the vapor phase is created in a closed volume. A special ampoule has been made for this purpose. Ge–Si is placed near one end of the ampoule. A temperature gradient is created along the ampoule. The temperature of the hot zone was chosen to be [Formula: see text]C and the temperature of the cold zone to be [Formula: see text]C. It has been found that single crystals can form not only on the polycrystalline layer, but also from separate centers on the walls of the ampoule.

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Vapor phase synthesis of fine particles

IEEE Transactions on Plasma Science ◽

10.1109/27.649619 ◽

1997 ◽

Vol 25 (5) ◽

pp. 1008-1016 ◽

Cited By ~ 23

Author(s):

A.C. Da Cruz ◽

R.J. Munz

Keyword(s):

Vapor Phase ◽

Fine Particles ◽

Phase Synthesis ◽

Vapor Phase Synthesis

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Vapor phase synthesis of Al-doped titania powders

Journal of Materials Research ◽

10.1557/jmr.1994.1241 ◽

1994 ◽

Vol 9 (5) ◽

pp. 1241-1249 ◽

Cited By ~ 61

Author(s):

Kamal M. Akhtar ◽

Sotiris E. Pratsinis ◽

Sebastian V.R. Mastrangelo

Keyword(s):

Vapor Phase ◽

Flow Reactor ◽

Particle Surface ◽

Particle Morphology ◽

High Concentration ◽

Phase Synthesis ◽

Transmission Electron ◽

Significant Enrichment ◽

Vapor Phase Synthesis ◽

Doped Titania

The role of aluminum as dopant in gas phase synthesis of titania powders was experimentally investigated in an aerosol flow reactor between 1300 and 1700 K. Titania was produced by vapor phase oxidation of titanium tetrachloride in the presence of dopant aluminum trichloride vapor. The presence of aluminum altered the particle morphology from polyhedral to irregular crystals. Energy dispersive analysis and transmission electron microscopy indicated that the powders were mixtures of crystalline titania and amorphous alumina. Analysis by XPS indicated significant enrichment of aluminum on the particle surface. Some aluminum titanate (up to 17% by volume) was formed at 1700 K when a high concentration of AlCl3 was used (AlCl3/TiCl4 ≥ 0.07). Measurements of lattice parameters by x-ray diffraction indicated that aluminum formed a solid solution in titania. While titania synthesized in the absence of aluminum was about 90% anatase, the introduction of aluminum resulted in pure rutile at AlCl3/TiCl4 = 0.07. The effects of aluminum on titania phase composition and morphology are explained by the creation of oxygen vacancies in the titania crystallites and by the enhancement of the sintring rate of titania grains.

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