Use of a design-of-experiments approach for preparing ceria–zirconia–alumina samples by sol–gel process

Dumont, Marcello Rosa; Nunes, Eduardo H.M.; Vasconcelos, Wander L.

doi:10.1016/j.ceramint.2016.03.021

Cited by 21 publications

(2 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This modification improves the catalytic performance in reactions such as Water Gas Shift, hydrocarbon steam reforming, and CO oxidation [29]. Adding zirconium into CeO 2 generates more oxygen vacancies, so these materials have better OSC and thermal stability [30,31]. Besides, Zr addition provides better catalytic activity at lower temperatures than CeO 2 [30].…”

Section: Introductionmentioning

confidence: 99%

Use of PdCu catalysts supported on zirconia-ceria based supports for the elimination of oxyanions present in water

et al. 2021

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Use of PdCu catalysts supported on zirconia-ceria based supports for the elimination of oxyanions present in water

et al. 2021

View full text Add to dashboard Cite

“…Ceria-zirconiaalumina samples synthesized by sol-gel process exhibited an increase in thermal instability at high temperature and high concentration of the ceria which was regulated with an increase in zirconia concentration [6]. According to the study conducted by Neto and Schmal [7] on iso-synthesis reaction with ceria and ceria-zirconia solid catalysts, strong basic sites and high selectivity was presented by ceria-zirconia as compared to ceria only.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Ce-Zr/Al-MCM-41 Bimetallic Catalyst for Transesterification of Jatropha Oil to Biodiesel

Jibril

Ramli

Jumbri

2018

IOP Conf. Ser.: Earth Environ. Sci.

View full text Add to dashboard Cite

Abstract.A series of bimetallic Ce-Zr heterogeneous catalysts supported on Al-MCM-41 aluminosilicate with cerium and zirconium loading ranging from 2.5 to 7.5 wt%, were prepared by co-impregnation method. The characterization of the catalysts obtained by various analytical methods; XRD, N2 adsorption-desorption, FESEM, EDX and TPD NH3. The result shows that metals were well incorporated in the framework of the support, catalysts retained the mesoporous character and stability of structure after impregnation. The catalysts were active in one step transesterification of non-edible jatropha oil to produce fatty acid methyl esters (FAME) with methanol to oil ratio 6:1 at 90˚C, after 4 h reaction time. The FAME yield was found to have the maximum activity, higher than 80% with catalyst 5 wt% Ce and 5 wt% Zr loadings supported by Al-MCM-41 with catalyst loading 5 wt%. The catalyst was recovered by simple filtration. IntroductionRecently, increasing attention has been paid to mesoporous molecular sieves having ordered hexagonal arrangements, high specific surface areas, and uniform pore diameters [1]. Modification of mesoporous aluminosilicates gives rise to a platform for wider application possibilities in industry and catalysis. The structurally stable mesoporous material, Al-MCM-41 has both hydrothermal stability and acidity properties unlike the parent material, MCM-41 [2].According to Avhad and Marchetti [3], an ideal catalyst should have superior activity and selectivity, be abundant, less expensive, durable, reusable, and be easy to separate. Although Al-MCM-41 have the requirements necessary for solid catalysts, the activity in alkyl ester conversion was found to be low and this weak performance was related to the acidity of the catalyst [4]. Active metals are incorporated into the framework of Al-MCM-41 as a support, in order to regulate the acidity. Moreover, catalyst efficiency depends on factors such as surface area, pore size and activity sites [5].Distribution of acid strength on the surface of molecular sieves is regulated to improve their activity, selectivity as well as the stability in biodiesel formation reaction processes. Ceria-zirconiaalumina samples synthesized by sol-gel process exhibited an increase in thermal instability at high temperature and high concentration of the ceria which was regulated with an increase in zirconia concentration [6]. According to the study conducted by Neto and Schmal [7] on iso-synthesis reaction with ceria and ceria-zirconia solid catalysts, strong basic sites and high selectivity was presented by ceria-zirconia as compared to ceria only.

show abstract

Selectivity of Ethanol Conversion on Al/Zr/Ce Mixed Oxides: Dehydration and Dehydrogenation Pathways Based on Surface Acidity Properties

et al. 2022

View full text Add to dashboard Cite

Zirconia-alumina mixed oxides (Zr + Ce)O 2 À Al 2 O 3 with various mol. ratios (5, 10, 20, 50, and 75 % alumina) were prepared using the sol-gel method. The catalysts were characterised via XRD, SEM, DTA/TG, BET, and FT-IR spectroscopy. The acidities of the catalysts were measured through the absorption of anthraquinone and pyridine probe molecules using EPR and IR spectroscopy, respectively. Catalytic activity and selectivity were investigated for ethanol conversion to acetaldehyde, ethylene, and diethyl ether, which were used as model reactions to identify surface-active sites. The relationship between the surface structure and the dehydration/dehydrogenation activity was evaluated. Diethyl ether formation is promoted by the presence of the ZrO 2 tetragonal phase at a low ZrO 2 /Al 2 O 3 ratio in the sample composition, at which the Lewis acid site has an aluminum-oxygen environment. The reaction mechanism was also discussed. In the low-temperature reaction region, dehydrogenation competes with dehydration; ethylene and acetaldehyde share a common reactive intermediate.

show abstract

Use of a design-of-experiments approach for preparing ceria–zirconia–alumina samples by sol–gel process

Cited by 21 publications

References 48 publications

Use of PdCu catalysts supported on zirconia-ceria based supports for the elimination of oxyanions present in water

Use of PdCu catalysts supported on zirconia-ceria based supports for the elimination of oxyanions present in water

Preparation and Characterization of Ce-Zr/Al-MCM-41 Bimetallic Catalyst for Transesterification of Jatropha Oil to Biodiesel

Selectivity of Ethanol Conversion on Al/Zr/Ce Mixed Oxides: Dehydration and Dehydrogenation Pathways Based on Surface Acidity Properties

Contact Info

Product

Resources

About