Hydrothermal reactions in lime-quartz pastes

1960 ◽  
Vol 10 (1) ◽  
pp. 7-15
Author(s):  
A. Aitken ◽  
H. F. W. Taylor
Keyword(s):  
Hydrothermal Reactions

scholarly journals Morphology Controlled Synthesis of γ-Al2O3 Nano-Crystallites in Al@Al2O3 Core–Shell Micro-Architectures by Interfacial Hydrothermal Reactions of Al Metal Substrates

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 310
Author(s):  
Dohyeon Han ◽  
Doohwan Lee
Keyword(s):  
Electrostatic Interactions ◽  
Heterogeneous Catalysts ◽  
Metal Substrate ◽  
Inorganic Anions ◽  
Core Shell ◽  
Hydroxyl Groups ◽  
Hydrothermal Reactions ◽  
Fine Control ◽  
Reaction Processes

Fine control of morphology and exposed crystal facets of porous γ-Al2O3 is of significant importance in many application areas such as functional nanomaterials and heterogeneous catalysts. Herein, a morphology controlled in situ synthesis of Al@Al2O3 core–shell architecture consisting of an Al metal core and a porous γ-Al2O3 shell is explored based on interfacial hydrothermal reactions of an Al metal substrate in aqueous solutions of inorganic anions. It was found that the morphology and structure of boehmite (γ-AlOOH) nano-crystallites grown at the Al-metal/solution interface exhibit significant dependence on temperature, type of inorganic anions (Cl−, NO3−, and SO42−), and acid–base environment of the synthesis solution. Different extents of the electrostatic interactions between the protonated hydroxyl groups on (010) and (001) facets of γ-AlOOH and the inorganic anions (Cl−, NO3−, SO42−) appear to result in the preferential growth of γ-AlOOH toward specific crystallographic directions due to the selective capping of the facets by adsorption of the anions. It is hypothesized that the unique Al@Al2O3 core–shell architecture with controlled morphology and exposed crystal-facets of the γ-Al2O3 shell can provide significant intrinsic catalytic properties with enhanced heat and mass transport to heterogeneous catalysts for applications in many thermochemical reaction processes. The direct fabrication of γ-Al2O3 nano-crystallites from Al metal substrate with in-situ modulation of their morphologies and structures into 1D, 2D, and 3D nano-architectures explored in this work is unique and can offer significant opportunities over the conventional methods.

scholarly journals Hydrothermal Synthesis of Various Shape-Controlled Europium Hydroxides

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 529
Author(s):  
Hongjuan Zheng ◽  
Kongjun Zhu ◽  
Ayumu Onda ◽  
Kazumichi Yanagisawa
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ph Value ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Hydrothermal Reactions ◽  
Starting Solution ◽  
Initial Ph ◽  
Shape Controlled ◽  
Scanning Electron

Eu(OH)3 with various shape-controlled morphologies and size, such as plate, rod, tube, prism and nanoparticles was successfully synthesized through simple hydrothermal reactions. The products were characterized by XRD (X-Ray Powder Diffraction), FE-SEM (Field Emission- Scanning Electron Microscopy) and TG (Thermogravimetry). The influence of the initial pH value of the starting solution and reaction temperature on the crystalline phase and morphology of the hydrothermal products was investigated. A possible formation process to control morphologies and size of europium products by changing the hydrothermal temperature and initial pH value of the starting solution was proposed.

Temperature- and pH-dependent mechanism of hydrogen production from hydrothermal reactions of sulfide

2012 ◽  
Vol 37 (24) ◽  
pp. 18679-18687 ◽  
Author(s):  
Putri Setiani ◽  
Noriaki Watanabe ◽  
Atsushi Kishita ◽  
Noriyoshi Tsuchiya
Keyword(s):  
Hydrogen Production ◽  
Hydrothermal Reactions ◽  
Ph Dependent ◽  
Dependent Mechanism

Rates of Hydrothermal Reactions

Science ◽  
1983 ◽  
Vol 222 (4622) ◽  
pp. 413-415 ◽  
Author(s):  
B. J. WOOD ◽  
J. V. WALTHER
Keyword(s):  
Hydrothermal Reactions

Hydrothermal Synthesis of Bi1.5ZnNb1.5O7 Nanopowders

2007 ◽  
Vol 561-565 ◽  
pp. 495-498 ◽  
Author(s):  
Jin Liang Huang ◽  
Xiao Wang ◽  
Liu Shuan Yang ◽  
Chun Wei Cui ◽  
Xing Hua Yang
Keyword(s):  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Pyrochlore Phase ◽  
Synthesis Temperature ◽  
Minimum Size ◽  
Hydrothermal Reactions ◽  
Prolonged Reaction Time ◽  
Scherrer Equation ◽  
Xrd Patterns

The cubic pyrochlore phase Bi1.5ZnNb1.5O7 nanopowder was successfully synthesized by the hydrothermal method (HTM) from the starting materials: Bi(NO3)3·5H2O, ZnO, Nb2O5 and the mineralizer: KOH. The XRD patterns prove that the cubic pyrochlore phase Bi1.5ZnNb1.5O7 nanopowder can be obtained by HTM, and TEM photographs show that the powders present the regularly granular shape, when the hydrothermal reactions were conducted at synthesis temperatures 140~220°C and reaction time for 6~48h. The crystalline sizes of the powders were calculated by the Scherrer equation to be about 43~49nm. The crystalline sizes decreased both with the increase in synthesis temperature and the prolonged reaction time until they reached to the minimum size about 43nm at 220°C for 24h.However, they tended to increase when the reaction time was above 24h.

Novel three-dimensional coordination polymers of lanthanides with sulfate and oxydiacetic acid

2013 ◽  
Vol 69 (12) ◽  
pp. 1503-1508 ◽  
Author(s):  
Thazhe Kootteri Prasad ◽  
M. V. Rajasekharan
Keyword(s):  
Crystal Structure ◽  
Coordination Polymers ◽  
Three Dimensional ◽  
Lanthanide Oxides ◽  
Coordination Polyhedra ◽  
Hydrothermal Reactions ◽  
Lanthanide Cations ◽  
Trigonal Prismatic Coordination ◽  
Oxydiacetic Acid ◽  
Trigonal Prismatic

Three three-dimensional coordination polymers,viz.poly[[diaqua-μ4-oxydiacetato-di-μ4-sulfato-dipraseodymium(III)] hemihydrate], [Pr2(C4H4O5)(SO4)2(H2O)2]·0.5H2O, (I), poly[[diaquadi-μ3-oxydiacetato-μ3-sulfato-dineodymium(III)] 1.32-hydrate], [Nd2(C4H4O5)2(SO4)(H2O)2]·1.32H2O, (II), and poly[[diaquadi-μ3-oxydiacetato-μ3-sulfato-disamarium(III)] 1.32-hydrate], [Sm2(C4H4O5)2(SO4)(H2O)2]·1.32H2O, (III), were obtained by hydrothermal reactions of the respective lanthanide oxides and ZnSO4with oxydiacetic acid (odaH2). The Nd3+and Sm3+compounds form isomorphous crystal structures in which the lanthanide cations are nine-coordinate, having a tricapped trigonal prismatic coordination. The Pr3+compound has an entirely different crystal structure in which two types of coordination polyhedra are observed,viz.nine-coordinate (trigonal prism) and ten-coordinate (bicapped square antiprism). The sulfate anions show various coordination modes, one of which has only rarely been observed crystallographically to date.

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