scholarly journals Influence of Vanadium Oxidation States on the Performance of V-Mg-Al Mixed-Oxide Catalysts for the Oxidative Dehydrogenation of Propane

2019 ◽  
Vol 54 (2) ◽  
Author(s):  
Leticia Schacht ◽  
Juan Navarrete ◽  
Persi Schacht ◽  
Marco A. Ramírez
Keyword(s):  
Catalytic Activity ◽  
Oxidative Dehydrogenation ◽  
Oxidation State ◽  
Mixed Oxide ◽  
Catalytic Performance ◽  
Oxide Catalysts ◽  
Oxidative Dehydrogenation Of Propane ◽  
Mixed Oxide Catalysts ◽  
Before And After ◽  
Temperature Programmed

V-Mg-Al mixed-oxide catalysts for oxidative dehydrogenation of propane were prepared by thermal decomposition of Mg-Al-layered double hydroxides with vanadium interlayer doping. The obtained catalysts were tested for the oxidative dehydrogenation of propane, obtaining good results in catalytic activity (conversion 16.55 % and selectivity 99.97 %). Results indicated that catalytic performance of these materials depends on how vanadium is integrated in the layered structure, which is determined by the Mg/Al ratio. Vanadium interlayer doping modifies the oxidation state of vanadium and consequently catalytic properties. Surface properties were studied by X-ray photoelectron spectroscopic and diffuse reflectance, UV-visible spectroscopy, and temperature programmed reduction (TPR). The analyses provided information about the oxidation state, before and after the reaction. From these results, it is suggested that selectivity to propylene and catalytic activity depend mainly on vanadium oxidation state.

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.

scholarly journals Statistically Guided Synthesis of MoV-Based Mixed-Oxide Catalysts for Ethane Partial Oxidation

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 370
Author(s):  
Juan Jimenez ◽  
Kathleen Mingle ◽  
Teeraya Bureerug ◽  
Cun Wen ◽  
Jochen Lauterbach
Keyword(s):  
Acetic Acid ◽  
Partial Oxidation ◽  
Mixed Oxide ◽  
Structural Integrity ◽  
Product Distribution ◽  
Catalytic Performance ◽  
Oxide Catalysts ◽  
Acid Yield ◽  
Mixed Oxide Catalysts ◽  
Catalyst Composition

The catalytic performance of Mo8V2Nb1-based mixed-oxide catalysts for ethane partial oxidation is highly sensitive to the doping of elements with redox and acid functionality. Specifically, control over product distributions to ethylene and acetic acid can be afforded via the specific pairing of redox elements (Pd, Ni, Ti) and acid elements (K, Cs, Te) and the levels at which these elements are doped. The redox element, acid element, redox/acid ratio, and dopant/host ratio were investigated using a three-level, four-factor factorial screening design to establish relationships between catalyst composition, structure, and product distribution for ethane partial oxidation. Results show that the balance between redox and acid functionality and overall dopant level is important for maximizing the formation of each product while maintaining the structural integrity of the host metal oxide. Overall, ethylene yield was maximized for a Mo8V2Nb1Ni0.0025Te0.5 composition, while acetic acid yield was maximized for a Mo8V2Nb1Ti0.005Te1 catalyst.

scholarly journals Combustion Synthesis of Non-Precious CuO-CeO2 Nanocrystalline Catalysts with Enhanced Catalytic Activity for Methane Oxidation

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 878 ◽  
Author(s):  
Abdallah Zedan ◽  
Amina AlJaber
Keyword(s):  
Solid Solution ◽  
Raman Spectroscopy ◽  
Catalytic Activity ◽  
Electronic Properties ◽  
Combustion Synthesis ◽  
Mixed Oxide ◽  
Oxide Catalysts ◽  
Ch4 Oxidation ◽  
X Ray ◽  
Mixed Oxide Catalysts

In this study, xCuO-CeO2 mixed oxide catalysts (Cu weight ratio x = 1.5, 3, 4.5, 6 and 15 wt.%) were prepared using solution combustion synthesis (SCS) and their catalytic activities towards the methane (CH4) oxidation reaction were studied. The combustion synthesis of the pure CeO2 and the CuO-CeO2 solid solution catalysts was performed using copper and/or cerium nitrate salt as an oxidizer and citric acid as a fuel. A variety of standard techniques, including scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were employed to reveal the microstructural, crystal, thermal and electronic properties that may affect the performance of CH4 oxidation. The CuO subphase was detected in the prepared solid solution and confirmed with XRD and Raman spectroscopy, as indicated by the XRD peaks at diffraction angles of 35.3° and 38.5° and the Ag Raman mode at 289 cm−1, which are characteristics of tenorite CuO. A profound influence of Cu content was evident, not only affecting the structural and electronic properties of the catalysts, but also the performance of catalysts in the CH4 oxidation. The presence of Cu in the CeO2 lattice obviously promoted its catalytic activity for CH4 catalytic oxidation. Among the prepared catalysts, the 6% CuO-CeO2 catalyst demonstrated the highest performance, with T50 = 502 °C and T80 = 556 °C, an activity that is associated with the availability of a fine porous structure and the enhanced surface area of this catalyst. The results demonstrate that nanocrystalline copper-ceria mixed oxide catalysts could serve as an inexpensive and active material for CH4 combustion.

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.

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