Ambient temperature NO oxidation over Cr-based amorphous mixed oxide catalysts: effects from the second oxide components

2017 ◽  
Vol 7 (11) ◽  
pp. 2362-2370 ◽  
Author(s):  
Aiyong Wang ◽  
Bo Lin ◽  
Hanlei Zhang ◽  
Mark H. Engelhard ◽  
Yanglong Guo ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Specific Surface ◽  
Mixed Oxide ◽  
Mixed Oxides ◽  
Sol Gel ◽  
No Oxidation ◽  
Gel Method ◽  
Mixed Oxide Catalysts ◽  
Surface Areas ◽  
Specific Surface Areas

Three series of Cr-based mixed oxides (Cr–Co, Cr–Fe, and Cr–Ni oxides) with high specific surface areas and amorphous textures were synthesized using a novel sol–gel method.

scholarly journals Variation of Gelatin Amount as Template for Mesoporous Silica-Alumina Synthesis based on Lapindo Mud

2020 ◽  
Vol 32 (7) ◽  
pp. 1575-1580
Author(s):  
R. Nuryanto ◽  
W. Trisunaryanti ◽  
Triyono
Keyword(s):  
Mesoporous Silica ◽  
Specific Surface ◽  
Surface Area ◽  
Sol Gel ◽  
Tem Analysis ◽  
Gel Method ◽  
Sol Gel Method ◽  
Surface Areas ◽  
Silica Alumina ◽  
Specific Surface Areas

The synthesis of mesoporous silica-alumina from Na2SiO3 and NaAlO2 solutions extracted from lapindo mud using mesoporous gelatin templates from catfish bone extract has been performed. Mesoporous silica-alumina (MSA) synthesis was carried out by sol-gel method with a gelatin template of catfish bone for as much as 0.0; 0.5; 1.0 and 1.5 g, which produced MSA-G00, MSA-G05, MSA-G10 and MSA-G15, respectively. The obtained MSA was analyzed using FTIR, XRD, TEM and surface area analyzer (BET and BJH methods). The MSA-G00, MSA-G05, MSA-G10 and MSA-G15 showed a specific surface areas of 24.58, 41.73, 59.73, 89.82 m2/g and pore diameters of 10.20, 3.86, 9.97, and 7.31 nm, respectively. The XRD results proved that all the MSA were amorphous while the TEM analysis showed that all prepared MSAs using gelatin as a template were wormhole-like pores

Preparation of TiO2-based powders with high photocatalytic activities

1997 ◽  
Vol 12 (3) ◽  
pp. 607-609 ◽  
Author(s):  
Tomoko Kasuga ◽  
Masayoshi Hiramatsu ◽  
Masayoshi Hirano ◽  
Akihiko Hoson ◽  
Kyoko Oyamada
Keyword(s):  
Specific Surface ◽  
Sol Gel ◽  
Photocatalytic Property ◽  
Reflection Spectra ◽  
Gel Method ◽  
Sol Gel Method ◽  
Surface Areas ◽  
Infrared Reflection ◽  
Photocatalytic Activities ◽  
Specific Surface Areas

TiO2-based powders doped with a small amount of SiO2 were prepared by a sol-gel method and subsequently were heated to precipitate fine anatase crystals. Although the obtained powders have large specific surface areas (≈200 m2 · g−1), they showed poorer activity in a photocatalytic property than the undoped TiO2 powders which have the area of 50 m2 · g−1. The SiO2-doped TiO2 powders were treated chemically with aqueous NaOH. Infrared reflection spectra showed that the treatment reduced the amount of SiO2 in the powders. The photocatalytic property of the powders was extremely improved by the treatment, and the powders showed higher activity than the undoped TiO2 powders.

Effect of Different Silicate Supports on the Catalytic Performance of MoVTeO Mixed Oxides in Partial Oxidation of Isobutane

2014 ◽  
Vol 12 (1) ◽  
pp. 623-628
Author(s):  
Jing Hu ◽  
Zhifang Li ◽  
Xiaoyuan Yang ◽  
Wenli Ding ◽  
Jingqi Guan
Keyword(s):  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Partial Oxidation ◽  
Mixed Oxides ◽  
Supported Catalysts ◽  
Catalytic Performance ◽  
Surface Areas ◽  
Specific Surface Areas ◽  
Mcm 41

Abstract A series of 5% MoV0.3Te0.25 supported on different silicates (i.e. SiO2, HMS, MCM-41, and MCM-48) have been prepared, characterized, and tested as catalysts in the partial oxidation of isobutane to methacrolein. Characterization results showed that the supports almost kept intact structures after supporting 5 wt.% MoV0.3Te0.25 and the supported catalysts had large specific surface areas. Catalytic tests showed that the specific surface area played a key role in the catalytic activity for the supported catalysts.

Elucidating the nature and role of copper species in catalytic carbonylation of methanol to methyl acetate over copper/titania–silica mixed oxides

2017 ◽  
Vol 7 (16) ◽  
pp. 3511-3523 ◽  
Author(s):  
Xianjie Meng ◽  
Heqin Guo ◽  
Qiang Wang ◽  
Yong Xiao ◽  
Congbiao Chen ◽  
...  
Keyword(s):  
Mixed Oxide ◽  
Methyl Acetate ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Copper Species ◽  
Gel Method ◽  
Sol Gel Method ◽  
Catalytic Carbonylation

In this study, a series of copper/titania–silica mixed oxide (Cu/TS) catalysts with different copper contents were prepared by a sol–gel method.

scholarly journals Effect of the Mg/Al Ratio on Activated Sol-Gel Hydrotalcites for Photocatalytic Degradation of 2,4,6-Trichlorophenol

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Esthela Ramos-Ramírez ◽  
Norma L. Gutiérrez-Ortega ◽  
Francisco Tzompantzi-Morales ◽  
Gloria A. Del Ángel ◽  
Claudia Martínez-Gómez ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Mixed Oxides ◽  
Thermal Evolution ◽  
Paper Industry ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Good Efficiency ◽  
X Ray ◽  
Mixed Oxide Catalysts ◽  
Surface Areas

Currently, interest has grown in finding effective solutions for the treatment of water pollution by toxic compounds. Some of the latter that have acquired importance are phenols and chlorophenols, due to their employment in the manufacture of pesticides, insecticides, cords of wood, paper industry, among others. The problem is rooted in that these compounds are very persistent in the environment because they are partially biodegradable and cannot be photodegraded directly by sunlight. Chlorophenols are extremely toxic, especially 2,4,6-trichlorophenol, which is potentially carcinogenic. In this work, Mg/Al-mixed oxide catalysts were obtained from the thermal treatment of hydrotalcite-type materials, synthesized by sol-gel method with different Mg/Al ratios. Hydrotalcites and Mg/Al-mixed oxides were physicochemically characterized by X-ray diffraction, thermal analysis (DTA and TGA), and N2 physisorption. The results were obtained on having proven the photocatalytic degradation of 2,4,6-trichlorophenol as a pollutant model by water. The catalysts obtained present the hydrotalcite phase with thermal evolution until achieving Mg/Al-mixed oxides at 500°C. The catalysts are of mesoporous materials and exhibiting large surface areas. The catalysts demonstrated good photocatalytic activity with good efficiency, reaching degradation percentages with Mg/Al = 1, 2, 4, 5, and 7 ratios of 94.2, 92.5, 86.2, 84.2, and 63.9%, respectively, until achieving mineralization.

Cerium–zirconium mixed oxide synthesized by sol-gel method and its effect on the oxygen vacancy and specific surface area

2021 ◽  
pp. 122752
Author(s):  
Pablo Teles Aragão Campos ◽  
Claudinei Fabiano Oliveira ◽  
João Pedro Vieira Lima ◽  
Daniele Renata de Queiroz Silva ◽  
Sílvia Cláudia Loureiro Dias ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mixed Oxide ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method

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.

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