NEW POSSIBILITIES OF LOW-TEMPERATURE GENERATION OF ACTIVE CENTERS DURING HETEROGENEOUS-HOMOGENEOUS ACTIVATION OF PROPANE ON SILICA GEL SURFACE, MODIFIED WITH ZnO BY THE SOL-GEL AND CHEICAL TRANSPORT REACTION METHODS

2021 ◽  
Vol 55 (1 (254)) ◽  
pp. 1-6
Author(s):  
Tatevik O. Kamalyan ◽  
Petros S. Gukasyan ◽  
Samvel M. Vardapetyan ◽  
Oleg A. Kamalyan
Keyword(s):  
Silica Gel ◽  
Sol Gel ◽  
Kinetic Method ◽  
Active Phase ◽  
Active Centers ◽  
Chemical Transport Reaction ◽  
Transport Reaction ◽  
Heterogeneous Catalytic ◽  
Surface Modified ◽  
The Given

By the example of heterogeneous catalytic oxidation of propane the process of peroxide radicals transfer from the surface of catalysts into the reactor volume is studied. For comparison ZnO/SiO2 contacts obtained by depositing the active phase on the silica surface by sol-gel and chemical transport reaction (CTR) were used. It was established that for the case both the temperature of the radicals transfer from the surface to the volume and the value of the activation energy are lower than in the case. It was shown that the modification of the silica gel surface with zinc oxide by the CTR method is more effective as compared with the sol-gel method. It is established that in both cases the active phase of the catalyst exhibits paramagnetic properties. On the basis of the given, semi-artificial kinetic method of radical detachment, the obligatory mechanism of activation failed.

scholarly journals Synergistic Effect of Alkali Na and K Promoter on Fe-Co-Cu-Al Catalysts for CO2 Hydrogenation to Light Hydrocarbons

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 735
Author(s):  
Yuhao Zheng ◽  
Chenghua Xu ◽  
Xia Zhang ◽  
Qiong Wu ◽  
Jie Liu
Keyword(s):  
Synergistic Effect ◽  
Active Sites ◽  
Intermediate Formation ◽  
Active Phase ◽  
Dissociative Adsorption ◽  
Co2 Hydrogenation ◽  
Chain Growth ◽  
Co2 Conversion ◽  
Light Hydrocarbons ◽  
Active Centers

Alkali metal K- and/or Na-promoted FeCoCuAl catalysts were synthesized by precipitation and impregnation, and their physicochemical and catalytic performance for CO2 hydrogenation to light hydrocarbons was also investigated in the present work. The results indicate that Na and/or K introduction leads to the formation of active phase metallic Fe and Fe-Co crystals in the order Na < K < K-Na. The simultaneous introduction of Na and K causes a synergistic effect on increasing the basicity and electron-rich property, promoting the formation of active sites Fe@Cu and Fe-Co@Cu with Cu0 as a crystal core. These effects are advantageous to H2 dissociative adsorption and CO2 activation, giving a high CO2 conversion with hydrogenation. Moreover, electron-rich Fe@Cu (110) and Fe-Co@Cu (200) provide active centers for further H2 dissociative adsorption and O-C-Fe intermediate formation after adsorption of CO produced by RWGS. It is beneficial for carbon chain growth in C2+ hydrocarbons, including olefins and alkanes. FeCoCuAl simultaneously modified by K-Na exhibits the highest CO2 conversion and C2+ selectivity of 52.87 mol% and 89.70 mol%, respectively.

scholarly journals Resistance to Growth of Molds for Wood Modified with Hydrophobic Hybrid Silica Gel Containing Copper Amine Complexes

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 577
Author(s):  
Shaokun Hao ◽  
Chuanshuang Hu ◽  
Xiuyi Lin ◽  
Jin Gu ◽  
Hong Yun ◽  
...  
Keyword(s):  
Silica Gel ◽  
High Efficiency ◽  
Copper Chloride ◽  
Sol Gel ◽  
Untreated Wood ◽  
Populus Tomentosa ◽  
Amine Complexes ◽  
Hybrid Silica ◽  
Sol Gel Process ◽  
Copper Amine

Complexation copper with amine provides an effective strategy for fixation copper in wood, while hydrophobic modification improves the dimensional stability of wood. Thus, a combination of complexation and hydrophobization is expected to enhance the efficiency of copper-based biocides. In this study, hydrophobic hybrid silica gel containing copper amine complexes (MACu) was prepared through an in situ sol-gel process in wood using methyltriethoxysilane (MTES), 3-amino-propyltriethoxysilane (APTES), and copper chloride. The resistance to growth of molds for MACu modified wood (Populus tomentosa) was measured according to ASTM D3273-16. A leaching resistance test was carried out in accordance with AWPA E11-16. The results showed that only Aspergillus niger covered the surface of untreated wood blocks and no mold grew on the MACu surface even after the leaching test. MACu xerogel and MACu wood were further characterized by SEM-EDS, FTIR, and XPS. A possible schematic diagram of the reaction mechanism was proposed to explain the high-efficiency anti-mold performance of MACu wood.

ChemInform Abstract: Sol-Gel Synthesis of Carbon/Silica Gel Electrodes for Lithium Intercalation.

ChemInform ◽  
2010 ◽  
Vol 31 (8) ◽  
pp. no-no
Author(s):  
Gerko Oskam ◽  
Peter C. Searson ◽  
T. Richard Jow
Keyword(s):  
Silica Gel ◽  
Sol Gel ◽  
Lithium Intercalation ◽  
Sol Gel Synthesis

Preparation of catalyst as Au doped Mn1Co9Ox/ceramic system for total oxidation of CO

2021 ◽  
Vol 10 (4) ◽  
pp. 39-45
Author(s):  
Phuong Pham Thi Mai ◽  
Hoan Nguyen Quoc ◽  
Quan Do Quoc ◽  
Hung Nguyen Thanh
Keyword(s):  
Sol Gel ◽  
Active Phase ◽  
Catalyst System ◽  
Oxidation Of Co ◽  
Sem Images ◽  
Total Oxidation ◽  
Wet Impregnation ◽  
Modern Analysis ◽  
Catalyst Powder ◽  
Xrd Patterns

In this paper, the Au doped Mn1Co9Ox was investigated for total oxidation of CO. The sol-gel method was applied to prepare this catalyst and some modern analysis methods as XRD, EPR, TPx, SEM were utilized to characterize its properties. The XRD patterns showed only Co3O4 phase without any peaks belonging to Mn or Au. However, the presence of Au and Mn was confirmed by EPR and O2-TPD results. With the aim to further apply catalyst in reality, the Au doped Mn1Co9Ox was deposited on ceramic by sol-gel, wet impregnation. The SEM images displayed the successful coating of active phase on substrate. However, the complete catalyst system didn’t have the high activity in total CO oxidation like the catalyst powder because of large agglomerations on coatings.

scholarly journals Liquid Phase Benzylation of Toluene over Modified Titania Catalysts

2012 ◽  
Vol 11 (2) ◽  
pp. 31-44
Author(s):  
Sunaja Devi K R ◽  
Sugunan S
Keyword(s):  
Liquid Phase ◽  
Lewis Acid ◽  
Benzyl Chloride ◽  
Sol Gel ◽  
Active Phase ◽  
Temperature Programmed Desorption ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Sulfated Titania ◽  
Temperature Programmed

Titania, sulfated titania and a series of iron loaded sulfated titania catalyst with different iron loadings (39 %) are prepared by sol-gel method and calcined at 500°C. Anatase is found to be the active phase with crystallite size in the nano range. All the prepared catalysts are found to be stable up to 700°C. Acidity is measured using spectrophotometric monitoring of adsorption of perylene, thermogravimetric desorption of 2,6-dimethylpyridine and temperature programmed desorption of ammonia. The activities of the catalysts were tested for liquid phase Friedel-Crafts benzylation of toluene with benzyl chloride. It has been concluded that Lewis acid sites are responsible for the reaction.

Nanocomposite Dielectric Material: Au/SiO2-gel

1992 ◽  
Vol 286 ◽  
Author(s):  
G.C. Vezzoli ◽  
M.F. Chen
Keyword(s):  
Silica Gel ◽  
Microprobe Analysis ◽  
Dielectric Material ◽  
Sol Gel ◽  
Dielectric Strength ◽  
Optimal Topology ◽  
Gold Chloride ◽  
Gel Technique ◽  
High Dielectric ◽  
Nanocomposite Dielectric

ABSTRACTA nanocomposite of clusters of gold atoms in a silica gel matrix has been prepared by the sol-gel technique through reduction of gold chloride. This composite was fabricated to explore novel techniques for materialsengineering new high dielectric strength substances for capacitor applications. The gold islands amidst the silica gel sea are materials-designed to utilize the percolation threshhold phenomenon to create a peak in the dielectricconstant as a function of optimal topology. Experimental results indicate an average dielectric constant of the order of 5000 at 1 kHz, and a maximum versus temperature at ∼ −100°C. Electron microscope and microprobe analysis indicate ellipsoidal Au particles or clusters of a dimension ranging from a hundred angstroms to several thousand angstroms.

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