Infrared spectra of carbon monoxide adsorbed on transition metal cation exchanged tin(IV) oxide

Harrison, Philip G.; Thornton, Edward W.

doi:10.1039/f19797501487

Cited by 20 publications

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“…These geminal polycarbonyls easily lose one (or more) of their CO ligands during evacuation at 85 K thus being converted into Mn 2þ -CO linear species. Analysis of the literature data [20,23,24,27,28] indicates that the oxidation state of manganese in the carbonyl complexes is indeed 2+.…”

Section: Adsorption Of Co On Mn-zsm-5mentioning

confidence: 99%

“…IR bands due to Mn nþ -CO surface complexes have been recorded at 2213-2172 cm À1 [20][21][22][23][24][25][26][27][28] and at 2144-2114 cm À1 [21,22,29]. These vibrations are generally assigned to Mn 2þ -CO species [20,23,24] but some authors [21,25,29] have reported that they characterise Mn 3þ -CO carbonyls.…”

Section: Introductionmentioning

confidence: 99%

“…These vibrations are generally assigned to Mn 2þ -CO species [20,23,24] but some authors [21,25,29] have reported that they characterise Mn 3þ -CO carbonyls. The surface complexes are easily decomposed after evacuation and are in some cases detected at low temperatures only, which indicates formation of an electrostatic and a r-bond only between manganese ions and CO. Carbonyls stable towards evacuation (band at 2213 cm À1 ) have been detected with Mn-ZSM-5 [27].…”

Section: Introductionmentioning

confidence: 99%

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FTIR study of low-temperature CO adsorption on Mn-ZSM-5 and MnY zeolites. Effect of the zeolite matrix on the formation of Mn2+(CO) geminal species

Hadjiivanov

Ivanova

Kantcheva

et al. 2002

Catalysis Communications

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Adsorption of CO on Mn-ZSM-5 zeolite at 85 K results in formation of physically adsorbed CO, several kinds of Hbonded CO and Mn 2þ ðCOÞ x geminal species ð2202 cm À1 Þ. Decreasing the coverage during evacuation results in disappearance of the physically adsorbed CO and the H-bonded forms and in conversion of the dicarbonyls to linear Mn 2þ -CO species ð2214 cm À1 Þ. The latter are quite stable at 85 K. Coadsorption 12 CO and 13 CO reveals that the CO molecules in the geminal polycarbonyls behave as independent oscillators. In contrast, CO adsorption at 85 K on MnNaY zeolite only leads to formation of linear Mn 2þ -CO species (2210 cm À1 ) and mono-and di-carbonyls associated with residual sodium cations. The results are interpreted as evidence that site-specified geminal carbonyls are formed with cations possessing an ionic radius bigger than a critical value. This value is different for different positions in various zeolites and is bigger for cations in S II positions in Y zeolites than is the case of cations in a ZSM-5 matrix. Ó

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Section: Adsorption Of Co On Mn-zsm-5mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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FTIR study of low-temperature CO adsorption on Mn-ZSM-5 and MnY zeolites. Effect of the zeolite matrix on the formation of Mn2+(CO) geminal species

Hadjiivanov

Ivanova

Kantcheva

et al. 2002

Catalysis Communications

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“…Extensive IR studies have been carried out to study this reaction [3][4][5] and to explore the surface reactions occurring at the tin(IV) oxide surface upon CO adsorption [6]. The experiments were carried out on oxide samples with and without transition metals as tin(IV) oxide itself has been shown to catalyze the oxidation of CO with 02 [7].…”

Section: Introductionmentioning

confidence: 99%

“…IR measurements carried out on tin(IV) oxide containing transition metals identified mainly physisorbed CO and different carbonate species adsorbed at the metal ion site [4]. Metal dependent v(CO) bands were detected in the IR spectrum and their frequencies were correlated with the calculated electric field strength at the adsorption site [5]. Nevertheless, it could not be unambiguously established whether species of the type M-CO and/or M-O ...CO were present.…”

Section: Introductionmentioning

confidence: 99%

A pulsed EPR study of the catalytic oxidation of CO over Cu/SnO2

et al. 1996

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The role of the Cu(II) in the catalytic oxidation of CO over Cu/SnO 2 with low Cu(II) content was studied by continuous wave EPR, electron spin echo envelope modulation (ESEEM) and hyperfine sublevel correlation (HYSCORE) spectroscopes. Three methods were employed for introducing the copper: (i) by coprecipitation, (ii) impregnation onto SnO 2 gel and (iii) impregnation onto calcined SnO 2. Two types of Cu(II) species were identified in these calcined Cu/SnO 2 matedals. Those belonging to the first type, termed B and C, exhibit highly resolved EPR spectra with well def'med EPR parameters and are located within the bulk of the oxide. The other group comprises a distribution of surface Cu(II) species with unresolved EPR features and are referred to as S. While the latter were readily reduced by CO the former required long exposures at high temperatures ( > 673 K). The specific interactions of the different Cu(II) species with CO were investigated through the determination of the 13C hyperfine coupling of enriched ~3CO. The ESEEM spectra of calcined samples, generated either by coprecipitation or impregnation, show after the adsorption of CO signals at the Larmor frequencies of .7, ll9Sn and t3C andat twice these Larmor frequencies.Although these signals indicate that llT, 1195n and 13C are in the close vicinity of Cu(II), they cannot provide the hyperfine couplings of these nuclei. This problem was overcome by the application of the HYSCORE experiment. The 2D HYSCORE spectra show well resolved cross peaks which provide the hyperfine interaction of these nuclei. Simulations of the HYSCORE spectra yield for 117,1198n ~ isotropic hyperfine constant, aiso, of +4.0 MHz and an anisotropic component, /'1, of +2.0 MHz. Pulsed ENDOR spectra also showed 117'119Sn signals which agree with the above values. The ~3C cross peaks yield ai~ o = + 1.0 MHz and Ti = +2.0 MHz. Similar C cross peaks were observed in spectra of calcined Cu/SnO 2 after the adsorption of CO 2. Based on the same hyperfine couplings in the samples exposed to 13CO and ~3CO2 the signals were assigned to surface carbonate species generated by part of the Cu(II) S type species rather then by species Band the role of the Cu(II) in the oxidation process is discussed.

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Infrared Spectroscopy for the Characterization of Surface Acidity and Basicity

Knözinger

2008

Handbook of Heterogeneous Catalysis

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Infrared spectra of carbon monoxide adsorbed on transition metal cation exchanged tin(IV) oxide

Cited by 20 publications

References 0 publications

FTIR study of low-temperature CO adsorption on Mn-ZSM-5 and MnY zeolites. Effect of the zeolite matrix on the formation of Mn2+(CO) geminal species

FTIR study of low-temperature CO adsorption on Mn-ZSM-5 and MnY zeolites. Effect of the zeolite matrix on the formation of Mn2+(CO) geminal species

A pulsed EPR study of the catalytic oxidation of CO over Cu/SnO2

Infrared Spectroscopy for the Characterization of Surface Acidity and Basicity

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