The nature of active chromium species in Cr-catalysts for dehydrogenation of propane: New insights by a comprehensive spectroscopic study

Kumar, M. Santhosh; Hammer, Nina; Rønning, Magnus; Holmén, Anders; Chen, De; Walmsley, John C.; Øye, Gisle

doi:10.1016/j.jcat.2008.11.014

Cited by 158 publications

(60 citation statements)

References 41 publications

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“…It should be noted that in the case of alumina-supported chromium catalysts, the nature (redox and non-redox) and nucleation of the active Cr(III) sites are still subject of discussion [23,24,30,41]. The content of redox and non-redox Cr sites as well as their nucleation varies with preparation procedures, origin of alumina and Cr content, therefore the estimation of which of the Cr(III) sites exhibits the highest activity and the contribution in the PDH is difficult.…”

Section: Resultsmentioning

confidence: 99%

“…In the case of Cr-containing catalysts, many factors, including the type of precursors, Cr loading, and the preparation procedure as well as the support nature, influence the distribution of Cr species at various oxidation states, which has a direct impact on the catalytic performance in the PDH process [19,20,21,22,23,24,25,26]. In oxidized alumina-supported chromium oxide catalysts, chromium is stabilized in three oxidation states—Cr(III), Cr(V) and Cr(VI) [19,21,24].…”

Section: Introductionmentioning

confidence: 99%

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Catalytic Behavior of Chromium Oxide Supported on Nanocasting-Prepared Mesoporous Alumina in Dehydrogenation of Propane

et al. 2017

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Mesoporous alumina with narrow pore size distribution centered in the range of 4.4–5.0 nm and with a specific surface area as high as 270 m2·g−1 was prepared via the nanocasting approach using a CMK-3 carbon replica as a hard template. Based on this support, a series of catalysts containing 1, 5, 10, 20 and 30 wt % of chromium was prepared by incipient wetness impregnation, characterized, and studied in the dehydrogenation of propane to propene (PDH). Cr species in three oxidation states—Cr(III), Cr(V) and Cr(VI)—were found on the oxidized surface of the catalysts. The concentration of these species varied with the total Cr loading. Temperature-programmed reduction (H2-TPR) and UV-Vis diffuse reflectance spectroscopy (UV-Vis-DRS) studies revealed that Cr(VI) species dominated at the lowest Cr content. An increase in the Cr loading resulted in an appearance of an increasing amount of Cr(III) oxide. UV-Vis-DRS measurements performed in situ during the PDH process showed that at the beginning of the catalytic test Cr(VI) species were reduced to Cr(III) redox species. A crucial role of the redox species in the PDH process over the catalysts with the low Cr content was confirmed. The stability test for the catalyst containing 20 wt % of Cr showed that this sample exhibited the reproducible catalytic performance after the first four regeneration–dehydrogenation cycles. Moreover, this catalyst had higher resistance on deactivation during the PDH process as compared to the reference catalyst with the same Cr loading, but was supported on commercially available alumina.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Catalytic Behavior of Chromium Oxide Supported on Nanocasting-Prepared Mesoporous Alumina in Dehydrogenation of Propane

et al. 2017

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“…This confirms the location of guest phase is at least in part trapped inside the micropores of the host material. Loss of active surface area through the introduction of a guest compound is commonly observed in silica/metal oxide nanocomposites such as Cr doped mesoporous silica SBA-15 [21].…”

Section: Resultsmentioning

confidence: 99%

Methyltrimethoxysilane (MTMS)-based silica–iron oxide superhydrophobic nanocomposites

Nadargi

Gurav

Marioni

et al. 2015

Journal of Colloid and Interface Science

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“…Propylene is an important feedstock employed in the production of a vast series of chemicals such as polypropylene and acrylonitrile . In recent years, propylene production from conventional paths could not match its increasing demand, thus propane dehydrogenation (PDH) has acquired considerable attention as an alternative propylene production technology .…”

Section: Introductionmentioning

confidence: 99%

Effects of Ga doping on Pt/CeO₂‐Al₂O₃ catalysts for propane dehydrogenation

et al. 2016

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This paper describes catalytic consequencesThis paper describes catalytic consequences of Pt/CeO 2 -Al 2 O 3 catalysts promoted with Ga species for propane dehydrogenation. A series of PtGa/CeO 2 -Al 2 O 3 catalysts were prepared by a sequential impregnation method. The as-prepared catalysts were characterized employing N 2 adsorption-desorption, X-ray diffrtaction, temperature programmed reduction, O 2 volumetric chemisorption, H 2 -O 2 titration, and transmission electron microscopy. We have shown that Ga 31 cations are incorporated into the cubic fluorite structure of CeO 2 , enhancing both lattice oxygen storage capacity and surface oxygen mobility. The enhanced reducibility of CeO 2 is indicative of higher capability to eliminate the coke deposition and thus is beneficial to the improvement of catalytic stability. Density functional theory calculations confirm that the addition of Ga is prone to improve propylene desorption and greatly suppress deep dehydrogenation and the following coke formation. The catalytic performance shows a strong dependence on the content of Ga addition. The optimal loading content of Ga is 3 wt %, which results in the maximal propylene selectivity together with the best catalytic stability against coke accumulation.

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The nature of active chromium species in Cr-catalysts for dehydrogenation of propane: New insights by a comprehensive spectroscopic study

Cited by 158 publications

References 41 publications

Catalytic Behavior of Chromium Oxide Supported on Nanocasting-Prepared Mesoporous Alumina in Dehydrogenation of Propane

Catalytic Behavior of Chromium Oxide Supported on Nanocasting-Prepared Mesoporous Alumina in Dehydrogenation of Propane

Methyltrimethoxysilane (MTMS)-based silica–iron oxide superhydrophobic nanocomposites

Effects of Ga doping on Pt/CeO₂‐Al₂O₃ catalysts for propane dehydrogenation

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The nature of active chromium species in Cr-catalysts for dehydrogenation of propane: New insights by a comprehensive spectroscopic study

Cited by 158 publications

References 41 publications

Catalytic Behavior of Chromium Oxide Supported on Nanocasting-Prepared Mesoporous Alumina in Dehydrogenation of Propane

Catalytic Behavior of Chromium Oxide Supported on Nanocasting-Prepared Mesoporous Alumina in Dehydrogenation of Propane

Methyltrimethoxysilane (MTMS)-based silica–iron oxide superhydrophobic nanocomposites

Effects of Ga doping on Pt/CeO2‐Al2O3 catalysts for propane dehydrogenation

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Effects of Ga doping on Pt/CeO₂‐Al₂O₃ catalysts for propane dehydrogenation