Isopentane dehydrogenation on Pt-Sn catalysts supported on Al-Mg-O mixed oxides: effect of Al/Mg atomic ratio

Armendáriz, H.; Guzmán, Ariel; Toledo, J. A.; Llanos, M. E.; Espinoza-Vázquez, Araceli; Aguilar‐Ríos, G.

doi:10.1016/s0926-860x(00)00836-x

Cited by 75 publications

(55 citation statements)

References 24 publications

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“…In order to confirm that the acidity of the spinel prepared by COPR is higher than those prepared by the other [30]. FTIR spectra of the ZnAl 2 O 4 spinels prepared by the three methods, shown in Fig.…”

Section: Synthesis and Characterization Of Znal 2 O 4 Supportsmentioning

confidence: 96%

Characterization of ZnAl2O4 Obtained by Different Methods and Used as Catalytic Support of Pt

et al. 2009

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In this work the synthesis of a ZnAl 2 O 4 spinel to be used as a support of metals and its characterization were studied. The methods used for the ZnAl 2 O 4 preparation were: ceramic method (CM), mechanochemical synthesis in humid medium (HMS) and coprecipitation (COPR). ZnAl 2 O 4 CM and ZnAl 2 O 4 HMS showed negligible acidity, but the ZnAl 2 O 4 COPR displayed a low acidity. The spinels obtained by COPR and HMS showed higher specific surface area and pore volumes than that prepared by the ceramic method. In addition the catalytic performance of Pt supported on the prepared spinel was evaluated in the n-butane dehydrogenation reaction. The Pt catalysts prepared with ZnAl 2 O 4 COPR presented better activity and selectivity to olefins than the ones prepared with ZnAl 2 O 4 HMS and ZnAl 2 O 4 CM, which could be correlated with a higher metallic dispersion and lower particle sizes, detected by TEM. The acidity of ZnAl 2 O 4 COPR, observed by isopropanol dehydration and TPD of pyridine, and the sequence of specific surface areas of the different spinels (ZnAl 2 O 4 COPR [ ZnAl 2 O 4 HMS [ ZnAl 2 O 4 CM) are other important factors to define the final dispersion of the catalysts.

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Section: Synthesis and Characterization Of Znal 2 O 4 Supportsmentioning

confidence: 96%

Characterization of ZnAl2O4 Obtained by Different Methods and Used as Catalytic Support of Pt

et al. 2009

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“…Over the Pt/MgAl 2 O 4 (curve a), two reduction peaks appear, one near 230°C and another around 470°C. Two types of Pt oxides are considered in literatures [29][30][31]. The former is reduced at low temperatures due to weak interaction with the support, the latter requires higher temperatures on account of strong interaction.…”

Section: Catalytic Propertiesmentioning

confidence: 99%

Propane Dehydrogenation Over PtSn Catalysts Supported on ZnO-Modified MgAl2O4

Wang

et al. 2009

Catal Lett

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Platinum and tin supported on ZnO-modified MgAl 2 O 4 constitutes a new and efficient catalyst for the dehydrogenation of propane. The structure of the catalyst has been studied by XRD, TEM, BET, TG, H 2 -TPR and H 2 chemisorption and catalytic properties for propane dehydrogenation have been tested on a microreactor. It has been shown that the catalyst is superior to conventional aluminasupported PtSn systems and PtSn/MgAl 2 O 4 in terms of lifetime stability, activity and propene selectivity. The characterization results of catalysts revealed that ZnOmodified catalysts can increase the Pt dispersion and enhance the interaction between metal and support, resulting in the increase of catalytic activity for propane dehydrogenation.

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“…Only a few reports in the open literature have been devoted to the system under study; Pt,Sn/Mg(Al)O [4,7,15,16,25,26]. The activity pattern of a proprietary 0.25wt%Pt,0.5wt%Sn/Mg(Al)O catalyst is quite peculiar, in that the initial activity increases during repeated dehydrogenation-regeneration cycles [15].…”

Section: And Refs Therein)mentioning

confidence: 99%

In situ XPS investigation of Pt(Sn)/Mg(Al)O catalysts during ethane dehydrogenation experiments

et al. 2007

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Calcined hydrotalcite with or without added metal (Mg(Al)O, Pt/Mg(Al)O and Pt,Sn/Mg(Al)O) have been investigated with in situ X-ray Photoelectron Spectroscopy (XPS) during ethane dehydrogenation experiments. The temperature in the analysis chamber was 450ºC and the gas pressure was in the range 0.3 -1 mbar. Depth profiling of calcined hydrotalcite and platinum catalysts under reaction, oxidation and in hydrogenwater mixture was performed by varying the photon energy, covering an analysis depth of 10-21 Å. It was observed that the Mg/Al ratio in the Mg(Al)O crystallites does not vary significantly in the analysis depth range studied. This result indicates that Mg and Al are homogeneously distributed in the Mg(Al)O crystallites. Catalytic tests have shown that the initial activity of a Pt,Sn/Mg(Al)O catalyst increases during an activation period consisting of several cycles of reduction -dehydrogenation -oxidation. The Sn/Mg ratio in a Pt,Sn/Mg(Al)O catalyst was followed during several such cycles, and was found to increase during the activation period, probably due to a process where tin spreads over the carrier material and covers an increasing fraction of the Mg(Al)O surface. The results further indicate that spreading of tin occurs under reduction conditions. A PtSn 2 alloy was studied separately. The surface of the alloy was enriched in Sn during reduction and reaction conditions at 450°C. Binding energies were determined and indicated that Sn on the particle surface is predominantly in an oxidized state under reaction conditions, while Pt and a fraction of Sn is present as a reduced Pt-Sn alloy.

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Isopentane dehydrogenation on Pt-Sn catalysts supported on Al-Mg-O mixed oxides: effect of Al/Mg atomic ratio

Cited by 75 publications

References 24 publications

Characterization of ZnAl2O4 Obtained by Different Methods and Used as Catalytic Support of Pt

Characterization of ZnAl2O4 Obtained by Different Methods and Used as Catalytic Support of Pt

Propane Dehydrogenation Over PtSn Catalysts Supported on ZnO-Modified MgAl2O4

In situ XPS investigation of Pt(Sn)/Mg(Al)O catalysts during ethane dehydrogenation experiments

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