IR investigations of CO2 adsorption on chromia surfaces: Cr2O3 (0001)/Cr(110) versus polycrystalline α-Cr2O3

Seiferth, Oliver; Wolter, Kai; Dillmann, B.; Klivényi, Gábor; Freund, Hans‐Joachim; Scarano, Domenica; Zecchina, Adriano

doi:10.1016/s0039-6028(98)00857-7

Cited by 159 publications

(148 citation statements)

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“…Part of the CO 2 derived species dissociates at the surface, leading to the production of vanadyl groups and CO. The results are very similar to the results obtained for CO 2 on Cr 2 O 3 (0001) [37] with the difference that surface reoxidation was not observed in the latter case.…”

Section: Discussionsupporting

confidence: 89%

“…Similar IRAS spectra as reported here for CO 2 on vanadium terminated V 2 O 3 (0001) were observed for CO 2 on chromium terminated Cr 2 O 3 (0001) [37]. However, neither CO 2 induced chromyl formation nor a CO 2 induced state near 1440 cm −1 were reported.…”

Section: (B)supporting

confidence: 87%

“…Seiferth et al [37] assign the infrared bands in the regime around 1300 cm −1 to the symmetric stretching vibration of a CO − 2 species with a local C 2V symmetry. For such a symmetry the dynamic dipole moment associated with the asymmetric stretching vibration would be mostly parallel to the surface which would result in a rather small cross section for infrared excitation and thus to a rather weak band in infrared spectra.…”

Section: (B)mentioning

confidence: 99%

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Carbon Dioxide Adsorption on V2O3(0001)

et al. 2017

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oxidation, selective reduction, and dehydrogenation of hydrocarbons and other organic compounds [1,2]. Examples are sulfuric acid production and the oxidation of butane to maleic anhydride [3]. The manifold of catalytic applications has triggered numerous fundamental research studies of vanadium oxides aiming to improve the microscopic understanding of the catalytic processes. A complete overview of the present state of the research cannot be given here; the reader is referred to the literature. Some aspects are summed up in recent review papers [2,[4][5][6][7][8][9]. Catalysts involving vanadium oxides are usually based on V 2 O 5 , which contains vanadium in its highest oxidation state +5, but under reaction conditions the oxidation state may be lower. Therefore the corundum type oxide V 2 O 3 has also been the topic of a number of studies (for an overview, see [2,9]). These studies benefited from the fact that V 2 O 3 layers with (0001) orientation can easily be grown on Au(111), Pd(111), Cu 3 Au(100) and W(110) [2,[9][10][11][12]. Adsorption studies have been performed for methanol [13,14], water [15,16], and O 2 [17]. The surface structure is a critical parameter for the reactivity of a material and therefore the structure of the V 2 O 3 (0001) surface has been investigated thoroughly. Guided mainly by the presence of an intense vanadyl induced feature in vibrational spectra [10,11] is was concluded that the surface should be terminated by a layer of vanadyl groups. This was questioned some years ago by studies which reported that the surface should be terminated by a quasi-hexagonal oxygen layer [18][19][20]. A later I/V-LEED (LEED = low energy electron diffraction; I/V-LEED = LEED intensity analysis) study could show that the initial picture of a vanadyl terminated surface is probably correct [21,22] and therefore we will use the term 'vanadyl terminated' throughout this text. The vanadyl terminated V 2 O 3 (0001) surface can be reduced by electron bombardment such that the oxygen atoms of the vanadyl Abstract The adsorption of carbon dioxide on epitaxially grown V 2 O 3 layers on Au(111) has been studied with thermal desorption and infrared absorption spectroscopy. It is shown that the as-grown grown oxide layer does not react with carbon dioxide; the molecule binds weakly to the surface, stays intact and desorbs below 200 K. If the oxide is weakly reduced such that part or all of the oxygen atoms of the surface vanadyl layer is removed, then a surface carboxylate, i.e. CO − 2 bound to surface vanadium is formed. Part of the CO 2 derived species decompose into O+CO upon annealing, with the oxygen atoms re-oxidizing the reduced oxide surface.

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Section: Discussionsupporting

confidence: 89%

Section: (B)supporting

confidence: 87%

Section: (B)mentioning

confidence: 99%

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Carbon Dioxide Adsorption on V2O3(0001)

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“…Here individual CO 2 -anions are also shown, formed at defect of the MgO film. The latter is quantitatively and qualitatively consistent with studies before through EPR titration of oxygen anions and IR measurements on CO 2 on other oxide films (Sterrer et al 2006;Seiferth et al 1999). However, at those defects, only a single electron transfer may be achieved.…”

Section: Examples 21 Supported Metal Particlessupporting

confidence: 90%

Models for heterogeneous catalysts: studies at the atomic level

Freund

2016

Rend. Fis. Acc. Lincei

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A systematic approach to model heterogeneous catalyst material and characterization at the atomic level is presented. Two examples are used to illustrate the concepts derived from those studies. They document the problems arising on the way to create such model systems and they also indicate possible solutions. The first example is connected with activation of CO 2 at the rim of electron rich MgO (thin film-supported Au islands), and the second example aims at the creation of a model system for the Phillips catalyst for ethylene polymerization and, in particular, the creation of a hydroxylated silica support.

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“…In previous studies, it was reported that CO 2 can be absorbed irreversibly on OH -groups (basic sites) producing CO 3 2-and H 2 O species [Cheng et al, 1998]. Therefore, an increase of the catalyst basicity can be assigned to the alkali-earth properties of barium [Yang and Kim, 2010;Zhang and Singh, 2008] and to the tendency to form carbonates on the chromium surfaces [Seiferth et al, 1999;Kuhlenbeck et al, 1992]. Figure 4 shows the IR transmission spectra of samples in the range 4000-400 cm -1…”

Section: Characterizationmentioning

confidence: 99%

VAPOR-PHASE CATALYTIC CONVERSION OF ETHANOL INTO 1,3-BUTADIENE ON Cr-Ba/MCM-41 CATALYSTS

La-Salvia

Lovón-Quintana

Valença

2015

Braz. J. Chem. Eng.

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-Al-MCM-41, 16%Ba/Al-MCM-41 and 1.4%Cr-16%Ba/Al-MCM-41 were used as catalysts in the vapor-phase catalytic conversion of ethanol. Physical-chemical properties of the catalysts and the effect of barium and chromium on the Al-MCM-41 activity and 1,3-butadiene yield were studied. The catalysts were characterized by X-ray diffraction (XRD), N 2 physisorption (BET method), CO 2 chemisorption and Fourier transform infrared spectroscopy (FT-IR). When ethanol was completely converted on Al-MCM-41 and 16%Ba/Al-MCM-41, the reaction products showed a high selectivity for ethylene (90-98%). However, on the 1.4%Cr-16%Ba/Al-MCM-41 catalyst, a greater number of reaction products were obtained such as ethylene, acetaldehyde, diethyl ether and 1,3-butadiene. The maximum 1,3-butadiene yield obtained from ethanol reaction was 25% at 723 K and W/F EtOH = 15 g h mol -1 . The latter result was obtained in a single step and without addition of reaction promoters (e.g., acetaldehyde, crotonaldehyde, hydrogen) in the feed stream to the reactor.

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IR investigations of CO2 adsorption on chromia surfaces: Cr2O3 (0001)/Cr(110) versus polycrystalline α-Cr2O3

Cited by 159 publications

References 53 publications

Carbon Dioxide Adsorption on V2O3(0001)

Carbon Dioxide Adsorption on V2O3(0001)

Models for heterogeneous catalysts: studies at the atomic level

VAPOR-PHASE CATALYTIC CONVERSION OF ETHANOL INTO 1,3-BUTADIENE ON Cr-Ba/MCM-41 CATALYSTS

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