Catalytic properties of copper–manganese mixed oxides prepared by coprecipitation using tetramethylammonium hydroxide

2014 ◽  
Vol 4 (10) ◽  
pp. 3713-3722 ◽  
Author(s):  
Hisahiro Einaga ◽  
Akihiro Kiya ◽  
Satoru Yoshioka ◽  
Yasutake Teraoka
Keyword(s):  
Aqueous Solution ◽  
Mixed Oxide ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Oxide Catalysts ◽  
Tetramethylammonium Hydroxide ◽  
Mixed Oxide Catalysts ◽  
Metal Nitrates ◽  
Copper Manganese ◽  
Coprecipitation Technique

Copper–manganese (Cu–Mn) mixed oxide catalysts were prepared by a coprecipitation technique from metal nitrates in aqueous solution using tetramethylammonium hydroxide (TMAH) as a pH regulator.

scholarly journals Co-Mn-Al Mixed Oxides Promoted by K for Direct NO Decomposition: Effect of Preparation Parameters

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 593 ◽  
Author(s):  
Pacultová ◽  
Bílková ◽  
Klegova ◽  
Karásková ◽  
Fridrichová ◽  
...  
Keyword(s):  
Mixed Oxide ◽  
Alkali Metals ◽  
Mixed Oxides ◽  
Oxide Catalysts ◽  
No Decomposition ◽  
Selective Catalyst ◽  
Mixed Oxide Catalysts ◽  
Preparation Conditions ◽  
Fundamental Research

Fundamental research on direct NO decomposition is still needed for the design of a sufficiently active, stable and selective catalyst. Co-based mixed oxides promoted by alkali metals are promising catalysts for direct NO decomposition, but which parameters play the key role in NO decomposition over mixed oxide catalysts? How do applied preparation conditions affect the obtained catalyst’s properties?

Activity studies of vanadium, iron, carbon and mixed oxides based catalysts for the oxidative dehydrogenation of ethylbenzene to styrene: a review

2015 ◽  
Vol 5 (12) ◽  
pp. 5062-5076 ◽  
Author(s):  
Itika Kainthla ◽  
Jayesh T. Bhanushali ◽  
Rangappa S. Keri ◽  
Bhari Mallanna Nagaraja
Keyword(s):  
Oxidative Dehydrogenation ◽  
Mixed Oxide ◽  
Active Carbon ◽  
Mixed Oxides ◽  
Oxide Catalysts ◽  
Mixed Oxide Catalysts ◽  
Vanadium Iron ◽  
Dehydrogenation Of Ethylbenzene ◽  
Oxidative Dehydrogenation Of Ethylbenzene ◽  
Carbon Based

The activity of V, Fe and carbon based catalysts depends on V5+, Fe3+and active carbon sites. The mixed oxide catalysts show superior activity than individual oxides.

scholarly journals Low Temperature deNOx Catalytic Activity with C2H4 as a Reductant Using Mixed Metal Fe-Mn Oxides Supported on Activated Carbon

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4341 ◽  
Author(s):  
Fang Liu ◽  
Li Yang ◽  
Jie Cheng ◽  
Xin Wu ◽  
Wenbin Quan ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Low Temperature ◽  
Mixed Oxide ◽  
Active Sites ◽  
Mixed Oxides ◽  
Catalytic Reduction ◽  
Oxide Catalysts ◽  
Catalyst Stability ◽  
No Conversion ◽  
Mixed Oxide Catalysts

The selective catalytic reduction of NOx (deNOx) at temperatures less than or at 200 °C was investigated while using C2H4 as the reductant and mixed oxides of Fe and Mn supported on activated carbon; their activity was compared to that of MnOx and FeOx separately supported on activated carbon. The bimetallic oxide compositions maintained high NO conversion of greater than 80–98% for periods that were three times greater than those of the supported monometallic oxides. To examine potential reasons for the significant increases in activity maintenance, and subsequent deactivation, the catalysts were examined by using bulk and surface sensitive analytical techniques before and after catalyst testing. No significant changes in Brunauer-Emmett-Teller (BET) surface areas or porosities were observed between freshly-prepared and tested catalysts whereas segregation of FeOx and MnOx species was readily observed in the mono-oxide catalysts after reaction testing that was not detected in the mixed oxide catalysts. Furthermore, x-ray diffraction and Raman spectroscopy data detected cubic Fe3Mn3O8 in both the freshly-prepared and reaction-tested mixed oxide catalysts that were more crystalline after testing. The presence of this compound, which is known to stabilize multivalent Fe species and to enhance oxygen transfer reactions, may be the reason for the high and relatively stable NO conversion activity, and its increased crystallinity during longer-term testing may also decrease surface availability of the active sites responsible for NO conversion. These results point to a potential of further enhancing catalyst stability and activity for low temperature deNOx that is applicable to advanced SCR processing with lower costs and less deleterious side effects to processing equipment.

scholarly journals Studies on the Binary MgO/SiO2 Mixed Oxide Catalysts for the Conversion of Ethanol to 1,3-Butadiene

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 854 ◽  
Author(s):  
Wladimir Reschetilowski ◽  
Matthias Hauser ◽  
Felix Alscher ◽  
Mandy Klauck ◽  
Grit Kalies
Keyword(s):  
Mixed Oxide ◽  
Mixed Oxides ◽  
Classical Method ◽  
Raw Materials ◽  
Chemical Properties ◽  
Oxide Catalysts ◽  
Mixed Oxide Catalysts ◽  
Ammonia Desorption ◽  
Optimum Chemical Composition ◽  
Temperature Programmed

The demand for 1,3-butadiene, one of the most important raw materials in the rubber industry, is constantly increasing. The Lebedev process is a classical method of producing 1,3-butadiene from ethanol, which is to be optimized with regard to the mixed oxide catalysts used. In this work, the binary MgO/SiO2 solid system was tested with regard to its optimum chemical composition for the catalytic conversion of ethanol to 1,3-butadiene. Furthermore, novel mesoporous mixed oxides were prepared to investigate their textural, structural, and surface chemical properties as well as the catalytic activity. Nitrogen physisorption, scanning electron microscopy (SEM), and temperature-programmed ammonia desorption (NH3-TPD) measurements were carried out and evaluated. It was shown that the optimum yield of 1,3-butadiene is achieved by using MgO/SiO2 mixed oxide catalysts with 85–95 mol% MgO and not, as suggested by Lebedev, with 75 mol% MgO. The NH3-TPD measurements revealed that the maximum acid-site density is achieved with an equimolar up to magnesium-rich composition. During the synthesis of binary MgO/SiO2 solid systems based on mesoporous MgO, a thermally stable and ordered structure was formed in the autoclave, depending on the carbonate used and on the duration of the treatment.

A Novel Active Ni-Ce-Al-Mixed Oxide Catalysts for Oxidative Dehydrogenation of Propane

2013 ◽  
Vol 724-725 ◽  
pp. 1098-1102 ◽  
Author(s):  
A. Ruheng ◽  
Jiang Wang ◽  
Zhao Ri Ge Tu Bao
Keyword(s):  
Oxidative Dehydrogenation ◽  
Mixed Oxide ◽  
Mixed Oxides ◽  
High Surface ◽  
High Surface Area ◽  
Oxide Catalysts ◽  
Coke Deposition ◽  
Oxidative Dehydrogenation Of Propane ◽  
Mixed Oxide Catalysts ◽  
Wide Range

Ni-Ce-Al layered double hydroxides (LDHs) with various Ni:Ce:Al molar ratios (3: 0.1:0.9, 3:0.2:0.8 and 3:0.5:0.5) were prepared by Co-precipitation. Ce can replace Al in a wide range of Ce/Al ratios to form Ni-Ce-Al-LDH with the unique layered structure of hydrotalcite. After the calcined at 600°C, LDHs samples were converted to mesoporous NiO-CeO2mixed oxides with a high surface area. The Ni-Ce-Al mixed oxide catalysts exhibit superior catalytic activity in oxidative dehydrogenation of propane and the excellent activities were attributed to mesoporous structure and the suppression of coke deposition.

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