Interplay between Defect Structure and Catalytic Activity in the Mo10−xVxOy Mixed-Oxide System

ChemPhysChem ◽  
2011 ◽  
Vol 12 (18) ◽  
pp. 3578-3583 ◽  
Author(s):  
Peter Jakes ◽  
Nina Blickhan ◽  
Tim Jekewitz ◽  
Alfons Drochner ◽  
Herbert Vogel ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Mixed Oxide ◽  
Defect Structure ◽  
Oxide System

LDH-derived catalysts for complete oxidation of volatile organic compounds

Clay Minerals ◽  
1999 ◽  
Vol 34 (1) ◽  
pp. 67-77 ◽  
Author(s):  
K. Bahranowski ◽  
E. Bielańska ◽  
R. Janik ◽  
T. Machej ◽  
E. M. Serwicka
Keyword(s):  
Catalytic Activity ◽  
Mixed Oxide ◽  
Copper Chromite ◽  
Oxide System ◽  
High Catalytic Activity ◽  
Commercial Catalyst ◽  
Volatile Organic ◽  
Double Hydroxides ◽  
Very High

AbstractThe Cu,Cr-, Zn,Cr- and Cu,Al-layered double hydroxides have been synthesized by the coprecipitation method and characterized by elemental analysis, PXRD, SEM/EDS and BET. The mixed oxide materials obtained upon calcination at 873 K show very high catalytic activity for the combustion of toluene and ethanol. The best sample is derived from the Cu,Cr-LDH precursor with a Cu:Cr ratio of 2, composed of copper oxide and copper chromite. This catalyst gave 50% conversion of toluene and ethanol at temperatures of 45 and 15 K lower, respectively, than the reference commercial catalyst. Catalytic tests with a mechanical mixture of CuO and CuCr2O4 demonstrate that the use of an LDH precursor is essential for optimum results. The importance of the simultaneous presence of both Cu and Cr, the influence of the Cu:Cr ratio on the catalytic activity and the role of the interface boundaries in the CuO-CuCr2O4 mixed oxide system are discussed.

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.

New mesoporous magnesium–aluminum mixed oxide and its catalytic activity in liquid phase Baeyer–Villiger oxidation reaction

2012 ◽  
Vol 71 ◽  
pp. 564-572 ◽  
Author(s):  
Manidipa Paul ◽  
Nabanita Pal ◽  
John Mondal ◽  
Manickam Sasidharan ◽  
Asim Bhaumik
Keyword(s):  
Catalytic Activity ◽  
Liquid Phase ◽  
Mixed Oxide ◽  
Oxidation Reaction ◽  
Villiger Oxidation

Ca-Sr-Ga-Nb mixed oxide system for high temperature superconductor substrate applications

1994 ◽  
Vol 139 (1-2) ◽  
pp. 54-66 ◽  
Author(s):  
S. Erdei ◽  
L.E. Cross ◽  
F.W. Ainger ◽  
A. Bhalla
Keyword(s):  
High Temperature ◽  
Mixed Oxide ◽  
High Temperature Superconductor ◽  
Oxide System

scholarly journals Evaluation of a Catalyst Durability in Absence and Presence of Toluene Impurity: Case of the Material Co2Ni2Mg2Al2 Mixed Oxide Prepared by Hydrotalcite Route in Methane Dry Reforming to Produce Energy

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1362
Author(s):  
Carole Tanios ◽  
Cédric Gennequin ◽  
Madona Labaki ◽  
Haingomalala Lucette Tidahy ◽  
Antoine Aboukaïs ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Mixed Oxide ◽  
Active Sites ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Side Reactions ◽  
Commercial Catalyst ◽  
Catalytic Sites ◽  
Catalyst Durability ◽  
Catalytic Performances

Ni, Co, Mg, and Al mixed-oxide solids, synthesized via the hydrotalcite route, were investigated in previous works toward the dry reforming of methane for hydrogen production. The oxide Co2Ni2Mg2Al2 calcined at 800 °C, Co2Ni2Mg2Al2800, showed the highest catalytic activity in the studied series, which was ascribable to an interaction between Ni and Co, which is optimal for this Co/Ni ratio. In the present study, Co2Ni2Mg2Al2800 was compared to a commercial catalyst widely used in the industry, Ni(50%)/Al2O3, and showed better activity despite its lower number of active sites, as well as lower amounts of carbon on its surface, i.e. less deactivation. In addition to this, Co2Ni2Mg2Al2800 showed stability for 20 h under stream during the dry reforming of methane. This good durability is attributed to a periodic cycle of carbon deposition and removal as well as to the strong interaction between Ni and Co, preventing the deactivation of the catalyst. The evaluation of the catalytic performances in the presence of toluene, which is an impurity that exists in biogas, is also a part of this work. In the presence of toluene, the catalytic activity of Co2Ni2Mg2Al2800 decreases, and higher carbon formation on the catalyst surface is detected. Toluene adsorption on catalytic sites, side reactions performed by toluene, and the competition between toluene and methane in the reaction with carbon dioxide are the main reasons for such results.

The catalytic activity and defect structure of zinc chromate

1991 ◽  
Vol 8 (5-6) ◽  
pp. 385-389 ◽  
Author(s):  
R. A. Jackson ◽  
C. R. A. Catlow ◽  
J. M. Thomas
Keyword(s):  
Catalytic Activity ◽  
Defect Structure ◽  
Zinc Chromate
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