Synthesis and physicochemical characterizations of nanostructured Pt/Al2O3–CeO2 catalysts for total oxidation of VOCs

Abbasi, Zahra; Haghighi, Mohammad; Fatehifar, Esmaeil; Saedy, Saeed

doi:10.1016/j.jhazmat.2010.12.034

Cited by 223 publications

(129 citation statements)

References 60 publications

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“…It has been found that the higher the dispersion and the smaller the size of the metal oxide particles, the lower the reduction peak temperature of the metal oxide in the TPR pattern will be (Kang et al, 2003;Soykal et al, 2012b). In addition, the shift to a lower reduction temperature observed for Co 10 /γ-Al 2 O 3 -CeO 2 can also be ascribed to the higher surface ceria concentration as well as the smaller size of the crystallites present in this sample, as indicated by the XRD and XPS measurements, respectively (Tables 1 and 2) (Abbasi et al, 2011). The position and intensity of the hydrogen consumption peaks may also indicate the surface oxygen mobility of some oxides, such as CeO 2 .…”

Section: Characterization Of the Catalystsmentioning

confidence: 81%

“…However, in all cases the best performance was observed for the catalysts supported on γ-Al 2 O 3 -CeO 2 . Appropriate combinations of metal oxides as catalyst supports may provide higher activity in oxidation reactions than single oxides, as reported by several authors (Luo et al, 2008;Abbasi et al, 2011;Barakat et al, 2012). Therefore, the discussion on the catalytic tests was focused on the former type of catalyst.…”

Section: Catalytic Activity Testsmentioning

confidence: 99%

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Catalytic oxidation of volatile organic compounds (n-hexane, benzene, toluene, o-xylene) promoted by cobalt catalysts supported on γ-Al2O3-CeO2

Balzer

Probst

Drago

et al. 2014

Braz. J. Chem. Eng.

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-Cobalt catalysts supported on γ-alumina, ceria and γ-alumina-ceria, with 10 or 20%wt of cobalt load, prepared by the wet impregnation method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission transmission electron microscopy (FETEM), N 2 adsorptiondesorption isotherms (BET/BJH methods), energy-dispersive X-ray spectroscopy (EDX), X-ray photoemission spectroscopy (XPS), O 2 -chemisorption and temperature programmed reduction (TPR) were used to promote the oxidation of volatile organic compounds (n-hexane, benzene, toluene and o-xylene). For a range of low temperatures (50-350 °C), the activity of the catalysts with a higher cobalt load (20% wt) was greater than that of the catalysts with a lower cobalt load (10% wt). The Co/γ-Al 2 O 3 -CeO 2 catalytic systems presented the best performances. The results obtained in the characterization suggest that the higher catalytic activity of the Co 20 /γ-Al 2 O 3 -CeO 2 catalyst may be attributed to the higher metal content and amount of oxygen vacancies, as well as the effects of the interaction between the cobalt and the alumina and cerium oxides.

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Section: Characterization Of the Catalystsmentioning

confidence: 81%

Section: Catalytic Activity Testsmentioning

confidence: 99%

Catalytic oxidation of volatile organic compounds (n-hexane, benzene, toluene, o-xylene) promoted by cobalt catalysts supported on γ-Al2O3-CeO2

Balzer

Probst

Drago

et al. 2014

Braz. J. Chem. Eng.

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“…Noble metal-based materials (e.g. Pt [9][10][11][12][13][14][15] and Pd [16][17][18][19][20][21] dispersed on various supports, such as Al2O3 [6, 9-10, 12, 14, 17, 19-20], ZrO2 [6,19] or TiO2 [16][17][18]), are usually studied in a role of catalysts of the VOCs combustion. They exhibit very high catalytic activity at relatively low temperatures, but are expensive and prone to deactivation by sintering or poisoning.…”

mentioning

confidence: 99%

Cobalt-containing BEA zeolite for catalytic combustion of toluene

Rokicińska

Drozdek

Dudek

et al. 2017

Applied Catalysis B: Environmental

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GRAPHICAL ABSTRACT Highlights-Controlled amounts of cobalt were homogeneously introduced in BEA structure.-Various forms of Co species were identified in Co-containing BEA structure.-After saturation of framework sites Co formed oxide clusters and crystallites.-The presence of Lewis acid sites resulted in enhanced selectivity to CO and benzene.-The highest activity showed Co-containing SiBEA with dominant contribution of Co3O4. AbstractCo-containing HAlBEA zeolite was obtained by conventional wet impregnation of HAlBEA zeolite with an aqueous Co(NO3)2 . 6 H2O solution, whereas Co-containing SiBEA zeolites were prepared by a two-step post-synthesis method. This approach consists of, in the first step, dealumination of parent BEA zeolite to obtain an aluminum-free SiBEA support and then, in the subsequent step, contact of the obtained material with an aqueous solution of cobalt nitrate. As shown by X-ray diffraction and low-temperature N2 adsorption, the dealumination of BEA zeolite and introduction of cobalt ions did not involve destruction of zeolite structure, and only insignificant blocking of pore system was observed after introduction of high amounts of cobalt. Nevertheless, clear changes in acidity were found by FTIR of pre-adsorbed pyridine after dealumination of parent BEA zeolite and introduction of cobalt ions. The presence of Lewis acid sites resulted in enhanced selectivity to CO and benzene formed as by-products in the toluene combustion. Therefore, SiBEA zeolite was chosen as a support for an introduction of various amounts of Co into the zeolite structure (the intended Co contents of 3.0 -9.0 wt %). Depended on the amount of the introduced Co, cobalt was incorporated into the framework of BEA zeolite as isolated mononuclear Co(II) species, small Co(II) oxide clusters and/or Co3O4 crystallites distributed in the whole zeolite structure.The chemical environment and dispersion of cobalt species were studied by transmission electron microscopy (TEM), FTIR of pre-adsorbed NO, UV-vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy (XPS). Temperature-programmed reduction of hydrogen (H2-TPR) was also performed to determine reducibility of the Cocontaining SiBEA zeolites. It was confirmed that siliceous SiBEA zeolite was the excellent support of Co3O4, which was in turn recognized as the main active phase in the total oxidation of toluene. The best catalytic performance was achieved over the catalysts containing at least 0.05 mmol of Co in the form of Co3O4 per 1 g of SiBEA zeolite.

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“…For the toluene combustion, the required temperature for 90% conversion of the bee's nestlike nanostructured CeO 2 Al 2 O 3 powders was lower for the sample calcined at 450°C and, for the sample calcined at 850°C, was closed to that reported for Pt/CeO 2 Al 2 O 3 nanocatalysts and for the £-Al 2 O 3 CeO 2 mixed oxide system prepared by the impregnation of boehmite with cerium nitrate and followed by calcinations. 14,15) However, the toluene conversion efficiency of the studied samples was still slightly lower than that observed for active CeO 2 catalyst. 8) From above studies, the highest catalytic activity in both m-xylene and toluene combustions obtained for the sample calcined at 450°C in comparison to that of other bee's nest-like nanostructured samples calcined at 600, 750 and 850°C might be attributed to its largest average pore size of 800 nm.…”

Section: Effects Of Calcination Temperature On the M-xylenementioning

confidence: 63%

“…14) To date, to our knowledge, no work has been reported on using for the CeO 2 Al 2 O 3 system as a catalyst for m-xylene while for the case of toluene only one research has been published. 15) In this work the catalytic activity in the m-xylene and toluene combustion of the bee's nest-like nanostructured CeO 2 Al 2 O 3 powders synthesized by combustion method using polyvinyl alcohol and metal nitrates as starting materials was presented.…”

Section: Introductionmentioning

confidence: 99%

Nanostructured CeO2–Al2O3 Catalytic Powders for m-Xylene and Toluene Combustion

et al. 2013

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The bee's nest-like nanostructured CeO 2 Al 2 O 3 powders were synthesized by combustion method using polyvinyl alcohol as a fuel and their catalytic activity were tested in the m-xylene and toluene combustion. The results showed that the catalytic reaction temperature increased monotonically from 200 to 250°C and from 250 to 300°C for the 90% conversion of m-xylene and toluene, respectively, with the calcination temperature in the range of 450850°C. For both combustions, the sample calcined at 450°C with a bee's nest-like nanostructure and average pore size of 800 nm exhibited the highest catalytic activity. Among the samples calcined at 850°C, the lowest catalytic reaction temperature for the 90% conversion of m-xylene and toluene of 250 and 300°C, respectively, was found with the sample having the equimolar ratio of Ce/Al.

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Synthesis and physicochemical characterizations of nanostructured Pt/Al2O3–CeO2 catalysts for total oxidation of VOCs

Cited by 223 publications

References 60 publications

Catalytic oxidation of volatile organic compounds (n-hexane, benzene, toluene, o-xylene) promoted by cobalt catalysts supported on γ-Al2O3-CeO2

Catalytic oxidation of volatile organic compounds (n-hexane, benzene, toluene, o-xylene) promoted by cobalt catalysts supported on γ-Al2O3-CeO2

Cobalt-containing BEA zeolite for catalytic combustion of toluene

Nanostructured CeO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub> Catalytic Powders for <i>m</i>-Xylene and Toluene Combustion

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Synthesis and physicochemical characterizations of nanostructured Pt/Al2O3–CeO2 catalysts for total oxidation of VOCs

Cited by 223 publications

References 60 publications

Catalytic oxidation of volatile organic compounds (n-hexane, benzene, toluene, o-xylene) promoted by cobalt catalysts supported on γ-Al2O3-CeO2

Catalytic oxidation of volatile organic compounds (n-hexane, benzene, toluene, o-xylene) promoted by cobalt catalysts supported on γ-Al2O3-CeO2

Cobalt-containing BEA zeolite for catalytic combustion of toluene

Nanostructured CeO<sub>2</sub>&ndash;Al<sub>2</sub>O<sub>3</sub> Catalytic Powders for <i>m</i>-Xylene and Toluene Combustion

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Nanostructured CeO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub> Catalytic Powders for <i>m</i>-Xylene and Toluene Combustion