Oxygen storage and catalytic NO removal promoted by CeO2-containing mixed oxides

1998 ◽  
Vol 275-277 ◽  
pp. 877-885 ◽  
Author(s):  
R Di Monte ◽  
P Fornasiero ◽  
M Graziani ◽  
J Kašpar
Keyword(s):  
Mixed Oxides ◽  
Oxygen Storage ◽  
No Removal

Role of Surface Adsorption in Fast Oxygen Storage/Release of CeO2 - ZrO2 Mixed Oxides

2007 ◽  
Vol 25 (4) ◽  
pp. 416-421 ◽  
Author(s):  
Xiaodong Wu ◽  
Qing Liang ◽  
Xiaodi Wu ◽  
Duan Weng
Keyword(s):  
Mixed Oxides ◽  
Surface Adsorption ◽  
Oxygen Storage

scholarly journals Effect of the Preparation Method on the Physicochemical Properties and the CO Oxidation Performance of Nanostructured CeO2/TiO2 Oxides

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 847 ◽  
Author(s):  
Sofia Stefa ◽  
Maria Lykaki ◽  
Dimitrios Fragkoulis ◽  
Vasileios Binas ◽  
Pavlos K. Pandis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Co Oxidation ◽  
Rational Design ◽  
Mixed Oxides ◽  
Oxygen Storage ◽  
Precipitation Method ◽  
Stöber Method ◽  
X Ray ◽  
Oxidation Performance ◽  
The Stöber Method

Ceria-based mixed oxides have been widely studied in catalysis due to their unique surface and redox properties, with implications in numerous energy- and environmental-related applications. In this regard, the rational design of ceria-based composites by means of advanced synthetic routes has gained particular attention. In the present work, ceria–titania composites were synthesized by four different methods (precipitation, hydrothermal in one and two steps, Stöber) and their effect on the physicochemical characteristics and the CO oxidation performance was investigated. A thorough characterization study, including N2 adsorption-desorption, X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscopy (TEM) and H2 temperature-programmed reduction (H2-TPR) was performed. Ceria–titania samples prepared by the Stöber method, exhibited the optimum CO oxidation performance, followed by samples prepared by the hydrothermal method in one step, whereas the precipitation method led to almost inactive oxides. CeO2/TiO2 samples synthesized by the Stöber method display a rod-like morphology of ceria nanoparticles with a uniform distribution of TiO2, leading to enhanced reducibility and oxygen storage capacity (OSC). A linear relationship was disclosed among the catalytic performance of the samples prepared by different methods and the abundance of reducible oxygen species.

Structure and Oxygen Storage Capacity of Pr/Nd Doped CeO2—ZrO2 Mixed Oxides.

ChemInform ◽  
2007 ◽  
Vol 38 (44) ◽  
Author(s):  
Xiaodi Wu ◽  
Xiaodong Wu ◽  
Qing Liang ◽  
Jun Fan ◽  
Duan Weng ◽  
...  
Keyword(s):  
Storage Capacity ◽  
Mixed Oxides ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
Doped Ceo2

Oxygen Storage Capacity of CexZr1-xO2 (0.4≤x≤0.8) Solid Solution Using Thermogravimetric Analysis

2013 ◽  
Vol 747 ◽  
pp. 579-582 ◽  
Author(s):  
N. Shanmuga Priya ◽  
Chandramohan Somayaji ◽  
S. Kanagaraj
Keyword(s):  
Solid Solution ◽  
Storage Capacity ◽  
Mixed Oxides ◽  
High Surface ◽  
High Surface Area ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
Co Precipitation ◽  
Good Number ◽  
High Oxygen Storage Capacity

The property of high oxygen storage capacity (OSC) of Ceria is an important component in three-way catalysts (TWC), which depends on the low reduction temperature, high surface area and stable crystalline structure. These are required to be improved using mixed oxides for the increased OSC of TWC. Though a good number of literature is available in Ceria-Zirconia mixed oxides, optimization of the composition of oxides based on OSC is very much limited. Hence, an attempt was made to optimize the composition of CexZr1-xO2 (0.4 x 0.8) (CZ) based on the OSC using thermogravimetric technique. The CZ solid solution was prepared by co-precipitation (COP) method using Ceria nitrate, and Zirconia oxy-choloride precursors, where the freshly prepared metal hydroxide precipitates were continuously stirred at 45 °C for 60 minutes followed by washing and drying to obtain the nanosized CZ particles. The formation of single nanocrystallite with less than 8 nm size solid solution was identified by XRD, and the same was confirmed by Micro Raman studies. It is observed that the trend of OSC in CZ solid solution was based on the ratio of Ce to Zr in the starting aqueous solution, where the OSC was found to be maximum at 1.5 and the corresponding OSC of the compound was about 0.14 μmol per gram of Ceria.

scholarly journals Effect of Sr on the properties of Ce-Zr-La mixed oxides

2006 ◽  
Vol 71 (3) ◽  
pp. 285-291 ◽  
Author(s):  
Richuan Rao ◽  
LI Lianyong ◽  
LI Fengyi
Keyword(s):  
Mixed Oxide ◽  
Storage Capacity ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
X Ray Diffraction ◽  
Pulse Technique ◽  
X Ray ◽  
Good Thermal Stability

Ce-Zr-La-Sr mixed oxides, with different Sr contents, were prepared by the sol-gel method. In a flow-system microreactor, the reduction properties and the oxygen storage capacity (OSC) of the Ce-Zr-La-Sr mixed oxides were investigated by a temperature programmed reduction (TPR) and a pulse technique. It was shown that the properties of the Ce-Zr-La mixed oxides depend on the Sr content and that the optimum Sr content in the Ce-Zr-La-Sr mixed oxide is 3 mol%. The Ce-Zr-La-Sr mixed oxides doped with 3 mol% Sr (Ce0.52Zr0.4La0.05Sr0.03O1.945) has the largest specific surface area and better reduction properties and oxygen storage capacity in comparison to the other investigated samples. The XRD results of the Ce-Zr-La-Sr mixed oxides showed that their X-ray diffraction patterns are well in agreement with that of fluorite-type CeO2 with Sr ions incorporated into the Ce-Zr-La mixed oxide structures. With increasing calcination temperature, the intensity of the X-ray diffraction peaks increased, but no new peaks were observed. All of these indicate that the synthesized samples had good thermal stability.

scholarly journals Hydrothermal Synthesis of ZnO–doped Ceria Nanorods: Effect of ZnO Content on the Redox Properties and the CO Oxidation Performance

2020 ◽  
Vol 10 (21) ◽  
pp. 7605
Author(s):  
Sofia Stefa ◽  
Maria Lykaki ◽  
Vasillios Binas ◽  
Pavlos K. Pandis ◽  
Vassilis N. Stathopoulos ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Co Oxidation ◽  
Rational Design ◽  
Mixed Oxides ◽  
Relevant Literature ◽  
Fine Tuning ◽  
Oxygen Storage ◽  
Doped Ceria ◽  
X Ray ◽  
Co Oxidation Reaction

The rational design of highly efficient, noble metal-free metal oxides is one of the main research priorities in the area of catalysis. To this end, the fine tuning of ceria-based mixed oxides by means of aliovalent metal doping has currently received particular attention due to the peculiar metal-ceria synergistic interactions. Herein, we report on the synthesis, characterization and catalytic evaluation of ZnO–doped ceria nanorods (NR). In particular, a series of bare CeO2 and ZnO oxides along with CeO2/ZnO mixed oxides of different Zn/Ce atomic ratios (0.2, 0.4, 0.6) were prepared by the hydrothermal method. All prepared samples were characterized by X-ray diffraction (XRD), N2 physisorption, temperature-programmed reduction (TPR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). The CO oxidation reaction was employed as a probe reaction to gain insight into structure-property relationships. The results clearly showed the superiority of mixed oxides as compared to bare ones, which could be ascribed to a synergistic ZnO–CeO2 interaction towards an improved reducibility and oxygen mobility. A close correlation between the catalytic activity and oxygen storage capacity (OSC) was disclosed. Comparison with relevant literature studies verifies the role of OSC as a key activity descriptor for reactions following a redox-type mechanism.

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