scholarly journals Catalytic Decomposition of an Energetic Ionic Liquid Solution over Hexaaluminate Catalysts

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 80 ◽  
Author(s):  
Sunghoon Hong ◽  
Sujeong Heo ◽  
Wooram Kim ◽  
Young Jo ◽  
Young-Kwon Park ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Surface Area ◽  
Sol Gel ◽  
Catalytic Decomposition ◽  
Liquid Solution ◽  
Catalytic Performance ◽  
Coprecipitation Method ◽  
Sol Gel Process ◽  
Α Al2o3 ◽  
Ionic Liquid Solution

The objective of this study was to determine the effect of a synthesis procedure of Sr hexaaluminate on catalytic performance during the decomposition of ionic liquid monopropellants based on ammonium dinitramide (ADN) and hydroxyl ammonium nitrate (HAN). Sr hexaaluminates were prepared via both coprecipitation and a sol–gel process. The surface area of hexaaluminate synthesized via the coprecipitation method was higher than that of hexaaluminate synthesized by the sol–gel process, and calcined at the same temperature of 1200 °C or more. This is because of the sintering of α-Al2O3 on the hexaaluminate synthesized via the sol–gel process, which could not be observed on the catalysts synthesized via the coprecipitation method. The hexaaluminate synthesized via coprecipitation showed a lower decomposition onset temperature during the decomposition of ADN- and HAN-based liquid monopropellants in comparison with the catalysts synthesized via the sol–gel process, and calcined at the same temperature of 1200 °C or more. This is attributed to the differences in the Mn3+ concentration and the surface area between the two hexaaluminates. Consequently, the hexaaluminate synthesized via coprecipitation which calcined above 1200 °C showed high activity during the decomposition of energetic ionic liquid monopropellants compared with the hexaaluminate synthesized via the sol–gel process.

scholarly journals Towards Macroporous α-Al2O3—Routes, Possibilities and Limitations

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1787
Author(s):  
Simon Carstens ◽  
Ralf Meyer ◽  
Dirk Enke
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Surface Areas ◽  
Alumina Membranes ◽  
Sol Gel Process ◽  
Specific Surface Areas ◽  
Α Al2o3 ◽  
Sol Gel Synthesis

This article combines a systematic literature review on the fabrication of macroporous α-Al2O3 with increased specific surface area with recent results from our group. Publications claiming the fabrication of α-Al2O3 with high specific surface areas (HSSA) are comprehensively assessed and critically reviewed. An account of all major routes towards HSSA α-Al2O3 is given, including hydrothermal methods, pore protection approaches, dopants, anodically oxidized alumina membranes, and sol-gel syntheses. Furthermore, limitations of these routes are disclosed, as thermodynamic calculations suggest that γ-Al2O3 may be the more stable alumina modification for ABET > 175 m2/g. In fact, the highest specific surface area unobjectionably reported to date for α-Al2O3 amounts to 16–24 m2/g and was attained via a sol-gel process. In a second part, we report on some of our own results, including a novel sol-gel synthesis, designated as mutual cross-hydrolysis. Besides, the Mn-assisted α-transition appears to be a promising approach for some alumina materials, whereas pore protection by carbon filling kinetically inhibits the formation of α-Al2O3 seeds. These experimental results are substantiated by attempts to theoretically calculate and predict the specific surface areas of both porous materials and nanopowders.

Decomposition of Ionic Liquid Solution Over CuIr-Hexaaluminate Catalysts

2020 ◽  
Vol 20 (7) ◽  
pp. 4466-4469
Author(s):  
Munjeong Kim ◽  
Jinwoo Kim ◽  
Hyojin Kim ◽  
Jeongsub Lee ◽  
Young Chul Park ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Physical Properties ◽  
Liquid Solution ◽  
Catalytic Performance ◽  
Ammonium Dinitramide ◽  
Liquid Propellant ◽  
Pellet Surface ◽  
Excellent Activity ◽  
Ionic Liquid Solution ◽  
Hexaaluminate Catalysts

The objective of this study is to elucidate the catalytic performance of hexaaluminate catalysts incorporating Cu and Ir simultaneously during the decomposition of an ammonium dinitramide (ADN)-based liquid propellant. Pellet-type catalysts were prepared and their chemico-physical properties were characterized by N2 adsorption, XRD, and XRF. It was confirmed that Cu and Ir atoms are well incorporated inside the hexaaluminate matrix of the Cu(x)Ir(10-x)-hexaaluminate catalysts and the content of Ir incorporated into hexaaluminte matrix was in the range of 2.5–8.2 wt%. The Cu(7)Ir(3)-hexaaluminate catalyst showed excellent activity in decomposition of ADN-based liquid monopropellant. The activity of the Cu(7)Ir(3)-hexaaluminate catalyst was much higher than that of the Cu(7)Ir(3)/hexaaluminate-imp catalyst prepared by impregnation of Cu and Ir onto the hexaaluminate pellet surface. This is attributed to the Cu and Ir being well incorporated in the hexaaluminate matrix and the dispersion of the Cu and Ir being greater in the Cu(7)Ir(3)-hexaaluminate than in the Cu(7)Ir(3)/hexaaluminate-imp.

Low temperature synthesis of ultrafine α-Al2O3 powder by a simple aqueous sol–gel process

2006 ◽  
Vol 32 (5) ◽  
pp. 587-591 ◽  
Author(s):  
Jiang Li ◽  
Yubai Pan ◽  
Changshu Xiang ◽  
Qiming Ge ◽  
Jingkun Guo
Keyword(s):  
Low Temperature ◽  
Sol Gel ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Al2o3 Powder ◽  
Sol Gel Process ◽  
Α Al2o3

Ultrahigh Surface Area Nanoporous Silica Particles via an Aero-Sol−Gel Process

Langmuir ◽  
2004 ◽  
Vol 20 (7) ◽  
pp. 2523-2526 ◽  
Author(s):  
S. H. Kim ◽  
B. Y. H. Liu ◽  
M. R. Zachariah
Keyword(s):  
Surface Area ◽  
Sol Gel ◽  
Silica Particles ◽  
Nanoporous Silica ◽  
Sol Gel Process

Texture Evaluation of Sol-Gel Derived Mesoporous Bioactive Glass

2013 ◽  
Vol 284-287 ◽  
pp. 230-234
Author(s):  
Yu Jen Chou ◽  
Chi Jen Shih ◽  
Shao Ju Shih
Keyword(s):  
Surface Area ◽  
Calcination Temperature ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Bioactive Glasses ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Adsorption Desorption

Recent years mesoporous bioactive glasses (MBGs) have become important biomaterials because of their high surface area and the superior bioactivity. Various studies have reported that when MBGs implanted in a human body, hydroxyl apatite layers, constituting the main inorganic components of human bones, will form on the MBG surfaces to increase the bioactivity. Therefore, MBGs have been widely applied in the fields of tissue regeneration and drug delivery. The sol-gel process has replaced the conventional glasses process for MBG synthesis because of the advantages of low contamination, chemical flexibility and lower calcination temperature. In the sol-gel process, several types of surfactants were mixed with MBG precursor solutions to generate micelle structures. Afterwards, these micelles decompose to form porous structures after calcination. Although calcination is significant for contamination, crystalline and surface area in MBG, to the best of the authors’ knowledge, only few systematic studies related to calcination were reported. This study correlated the calcination parameters and the microstructure of MBGs. Microstructure evaluation was characterized by transmission electron microscopy and nitrogen adsorption/desorption. The experimental results show that the surface area and the pore size of MBGs decreased with the increasing of the calcination temperature, and decreased dramatically at 800°C due to the formation of crystalline phases.

The Partitioning of Americium and the Lanthanides Using Tetrabutyldiglycolamide (TBDGA) in Octanol and in Ionic Liquid Solution

2012 ◽  
Vol 30 (7) ◽  
pp. 735-747 ◽  
Author(s):  
M. E. Mincher ◽  
D. L. Quach ◽  
Y. J. Liao ◽  
B. J. Mincher ◽  
C. M. Wai
Keyword(s):  
Ionic Liquid ◽  
Liquid Solution ◽  
Ionic Liquid Solution
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