Effect of CexZryLazOδ Mixed Oxides on the Structural and Catalytic Behavior of Monometallic Catalytic Converters Under Simulated Exhaust Conditions

2009 ◽  
Vol 52 (13-20) ◽  
pp. 1873-1879 ◽  
Author(s):  
V. Matsouka ◽  
M. Konsolakis ◽  
I. V. Yentekakis ◽  
A. Papavasiliou ◽  
A. Tsetsekou
Keyword(s):  
Mixed Oxides ◽  
Catalytic Converters ◽  
Catalytic Behavior ◽  
Simulated Exhaust Conditions

Effect of the Ration of Cu to Mn on the Activity and Stability of Copper-Manganese Mixed-Oxides for the Water Gas Shift Reaction

2013 ◽  
Vol 634-638 ◽  
pp. 518-521 ◽  
Author(s):  
Ke Duan Zhi ◽  
Quan Sheng Liu ◽  
Run Xia He ◽  
Fang Wu ◽  
Ya Gang Zhang ◽  
...  
Keyword(s):  
Surface Area ◽  
Mixed Oxides ◽  
Water Gas Shift ◽  
Water Gas Shift Reaction ◽  
Catalyst Structure ◽  
Catalytic Behavior ◽  
Stable Catalyst ◽  
Copper Manganese ◽  
Shift Reaction ◽  
Water Gas

The effects of Cu/Mn ratio on the activity and stability of Cu-Mn catalysts for the water-gas shift reaction (WGSR) were investigated. Activity tests showed that the Cu-Mn catalyst while the ration of Cu to Mn is 1:1 displayed higher activity and better stability than that of others catalysts. The BET , XRD and TPR results revealed that the Cu-Mn catalyst while the ration of Cu to Mn is 1:1 led to higher surface area, a more stable catalyst structure and suitable reduction performance, in turn leading to better catalytic behavior for the Cu-Mn catalyst.

Flame-made MgAl2−xMxO4 (M=Mn, Fe, Co) mixed oxides: Structural properties and catalytic behavior in methane combustion

2010 ◽  
Vol 97 (3-4) ◽  
pp. 398-406 ◽  
Author(s):  
Niels van Vegten ◽  
Tinku Baidya ◽  
Frank Krumeich ◽  
Wolfgang Kleist ◽  
Alfons Baiker
Keyword(s):  
Structural Properties ◽  
Mixed Oxides ◽  
Methane Combustion ◽  
Catalytic Behavior

The Influence Of The Support On The Deactivation Behaviour of Pt-Sn Reforming Catalysts

2005 ◽  
Vol 3 (1) ◽  
Author(s):  
Ignacio Contreras ◽  
Gustavo Pérez ◽  
Tomás Viveros
Keyword(s):  
Active Sites ◽  
Catalyst Deactivation ◽  
Mixed Oxides ◽  
Kinetic Constant ◽  
Coke Formation ◽  
Formation Kinetic ◽  
Catalytic Behavior ◽  
Reforming Catalysts ◽  
Metal Support Interaction ◽  
S Model

The effect of Al2O3-ZrO2, Al2O3-TiO2 and Al2O3-La2O3 mixed oxides on the deactivation of bifunctional Pt-Sn/ Al2O3 reforming catalysts has been investigated. The n-heptane reforming at 500°C was used as a test reaction. Changes in the catalytic behavior due to differences of the acidity and the support-metal interaction were observed. Levenspiel´s and Beltramini´s deactivation models were developed assuming a series fouling for the carbonaceous deposits. Through the Beltramini’s model it was possible to distinguish the amount of acidity that participates in the deactivation processes. Both models successfully correlated with the experimental profiles of n-heptane activity decay. The following deactivation decreasing order, Al2O3-TiO2-1>Al2O3-ZrO2-25>Al2O3-TiO2-2> Al2O3>Al2O3-La2O3-10 was found with both deactivation models. A quasi-linear correlation between the deactivation order and the coke formation kinetic constant (Levenspiel’s parameters) was observed. The catalyst acidity and the n-heptane conversion were correlated with Beltramini’s model. It was found that a high acidity (12 X 10-17 acid sites/g cat.) or metal dispersion (83%) increases the catalyst deactivation and it is necessary to have a balance of active sites in order to have a catalyst working as a bifunctional catalyst. On the other hand, the auto-regeneration Beltramini’s parameter suggests that the lowest deactivation of the Pt-Sn/ Al2O3-La2O3-10 catalyst is attributed to the cleaning capacity of the active sites. It was observed that the highest deactivation (80-92%) of the platinum-tin catalysts supported in alumina-titania mixed oxides were a result of the strong metal-support interaction (SMSI) effect. The Pt-Sn/Al2O3-La2O3-10 showed the best catalytic behavior with high initial and residual conversions (70 and 48%, respectively) and low deactivation (17 %) at a 50-minute reaction time. Furthermore, in the Pt-Sn/Al2O3 catalyst, the benzene yield was 1%, while the Pt-Sn/Al2O3-La2O3-10 showed a total inhibition of benzene production yield at residual conversions.

Preparation of Cu/Co/Fe Mixed Oxides and their Catalytic Behavior on HC-SCR DeNOx

2014 ◽  
Vol 1033-1034 ◽  
pp. 1058-1062 ◽  
Author(s):  
Hong Bo Liu ◽  
Zhi Yong Huang ◽  
Lin Jie Li ◽  
Jun Ting Huang ◽  
Zhi Cong He ◽  
...  
Keyword(s):  
Mixed Oxides ◽  
Catalytic Reduction ◽  
Homogeneous Distribution ◽  
Catalytic Behavior ◽  
Reduction Of No ◽  
Catalytic Activities ◽  
Structure And Morphology ◽  
Surface Areas ◽  
Nox Conversion ◽  
Specific Surface Areas

Co/Cu/Fe mixed oxides (Co/Cu/Fe-MOs) were prepared by calcination of Cu/Co/Fe hydrotalcites (Co/Cu/Fe-HTs) precursors. Their structure and morphology were characterized by XRD, TGA, IR and SEM. Co/Cu/Fe-MOs were used for selective catalytic reduction of NO by hydrocarbon. Their catalytic activities were studied by NOx analyzer. The results show that Co/Cu/Fe-MOs have homogeneous distribution of hexagon with particles size around 30~50nm and the specific surface areas are around 70~110 m2∙g–1. Cu2Co8Fe5-MOs sample exhibits the highest NOx conversion of 32%. Co/Cu/Fe-MOs with lower calcination temperature have higher catalytic activities.

Copper-Based Mixed Oxides Catalyst of Water-Gas Shift Reaction for Fuel Cells: The Role of Alkali Charge

2012 ◽  
Vol 268-270 ◽  
pp. 538-541
Author(s):  
Ke Duan Zhi ◽  
Quan Sheng Liu ◽  
Run Xia He ◽  
Fang Wu ◽  
Ya Gang Zhang ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Surface Area ◽  
Mixed Oxides ◽  
Water Gas Shift ◽  
Water Gas Shift Reaction ◽  
Catalyst Structure ◽  
Catalytic Behavior ◽  
Shift Reaction ◽  
Water Gas

The effects of alkali charge on the activity and stability of copper-based mixed oxides catalyst for the water-gas shift reaction (WGSR) were investigated. Activity tests showed that the copper-based mixed oxides catalyst while the 2[NaOH]/[Cu2++Mn2+] is above 1.2 displayed higher activity and better stability than that of others catalysts. The BET , XRD and TPR results revealed that the Cu-Mn catalyst while the 2[NaOH]/[Cu2++Mn2+] is above 1.2 led to higher surface area, a more stable catalyst structure and suitable reduction performance, in turn leading to better catalytic behavior for the Cu-Mn catalyst.

scholarly journals Effect of the presence of CuOx on the catalytic behavior of bimetallic Au-Cu catalyst supported on Ce-Zr mixed oxide in CO preferential oxidation

2019 ◽  
Vol 39 (2) ◽  
Author(s):  
Juan David Arevalo ◽  
Julio César Vargas ◽  
Luis Fernando Córdoba
Keyword(s):  
Copper Oxide ◽  
Mixed Oxide ◽  
Bimetallic Catalyst ◽  
Mixed Oxides ◽  
Copper Catalyst ◽  
Gold Catalyst ◽  
Nano Particles ◽  
Preferential Oxidation ◽  
Catalytic Behavior ◽  
Catalytic Materials

The effect of the presence of copper was evaluated on a bimetallic catalyst Au-Cu based on mixed oxide cerium-zirconium in the preferential oxidation of CO (CO-PROX). Six catalytic materials, based on mixed oxides, were prepared: (1) the support (CeZr); (2) the monometallic catalysts, i.e. gold (Au/CeZr), (3) impregnated copper oxide (CuOx/CeZr) and (4) incorporated copper (CuCeZr); and the bimetallic catalysts, i.e. (5) impregnated copper oxide and gold (Au-CuOx/CeZr), and (6) gold and incorporated copper (Au/CuCeZr). The catalysts were evaluated in the CO-PROX in the range 30-300°C and atmospheric pressure, where the Au-CuOx/CeZr showed the best catalytic behavior. The influence of CO2 and H2O in the feed stream was evaluated on the catalytic performance of the Au-CuOx/CeZr. An inhibitory effect for the CO2 was observed, while the presence of H2O enhanced the performance. Additionally, the catalytic stability was evaluated, reaching CO conversion of 93% and selectivity of 90% for 118 h. The catalytic materials were characterized by XRD, showing in all cases the fluorite cubic structure. The N2 adsorption-desorption analyses showed that synthesized materials were mesoporous and the TPR-H2 test reveals that the presence of the active phase increases the reducibility of Ce4+ to Ce3+. Reduction peaks of the gold catalyst were present at lower temperatures than those of the copper catalyst, which is related to a hydrogen spillover phenomenon. Finally, the samples were analyzed by SEM and TEM, which confirmed the formation of nano-particles with a diameter of about 4 nm.

Synthesis, Characterization, and Catalytic Behavior of Mg–Al–Zn–Fe Mixed Oxides from Precursors Layered Double Hydroxide

2011 ◽  
Vol 50 (11) ◽  
pp. 6695-6703 ◽  
Author(s):  
Angélica C. Heredia ◽  
Marcos I. Oliva ◽  
Carlos I. Zandalazini ◽  
Ulises A. Agú ◽  
Griselda A. Eimer ◽  
...  
Keyword(s):  
Layered Double Hydroxide ◽  
Mixed Oxides ◽  
Catalytic Behavior ◽  
Double Hydroxide

Mg–Fe–Al mixed oxides with mesoporous properties prepared from hydrotalcite as precursors: Catalytic behavior in ethylbenzene dehydrogenation

2005 ◽  
Vol 288 (1-2) ◽  
pp. 220-231 ◽  
Author(s):  
Yoshihiko Ohishi ◽  
Tomonori Kawabata ◽  
Tetsuya Shishido ◽  
Ken Takaki ◽  
Qinghong Zhang ◽  
...  
Keyword(s):  
Mixed Oxides ◽  
Catalytic Behavior ◽  
Ethylbenzene Dehydrogenation
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