The formation of a well defined rhodium dicarbonyl in highly dealuminated rhodium-exchanged zeolite Y by interaction with CO

Mießner, H.; Burkhardt, I.; Gutschick, D.; Zecchina, Adriano; Morterra, C.; Spoto, G.

doi:10.1039/f19898502113

Cited by 83 publications

(123 citation statements)

References 8 publications

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“…[10] The bands in the n OH region representing OH groups in the zeolite framework decreased in intensity upon incorporation and oxidation of the platinum complexes. After oxidation, the band at 3743 cm À1 , assigned to zeolite silanol groups, [11] was the only n OH band remaining, consistent with the expectation that the platinum complexes had preferentially undergone ion exchange with K + ions located near zeolite Al atoms rather than Si atoms. [12,13] Pt L III edge EXAFS spectra of this catalyst (Table 1; for fitting details, see the Supporting Information) are in accord with the IR data, indicating a Pt À N shell with a coordination number of nearly 4.…”

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confidence: 77%

A Single‐Site Platinum CO Oxidation Catalyst in Zeolite KLTL: Microscopic and Spectroscopic Determination of the Locations of the Platinum Atoms

Kistler

Chotigkrai

et al. 2014

Angewandte Chemie

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A stable site-isolated mononuclear platinum catalyst with a well-defined structure is presented. Platinum complexes supported in zeolite KLTL were synthesized from [Pt(NH 3 ) 4 ]-(NO 3 ) 2 , oxidized at 633 K, and used to catalyze CO oxidation. IR and X-ray absorption spectra and electron micrographs determine the structures and locations of the platinum complexes in the zeolite pores, demonstrate the platinumsupport bonding, and show that the platinum remained site isolated after oxidation and catalysis.

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supporting

confidence: 77%

A Single‐Site Platinum CO Oxidation Catalyst in Zeolite KLTL: Microscopic and Spectroscopic Determination of the Locations of the Platinum Atoms

Kistler

Chotigkrai

et al. 2014

Angewandte Chemie

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“…The former are generally attributed to linear Rh-bonded CO vibrations and the latter to bridge Rh-coordinated CO. The presence of both types of species in Rh supported on macroporous materials 6,12,13,15-17,31,33,34,43-52 and zeolites 16,17,19,32,53 has been widely reported.…”

Section: Resultsmentioning

confidence: 99%

“…16,54 It results in two bands in the CO IR spectrum: one in-phase CO stretching vibration between 2118 and 2070 cm -1 and one out-of-phase stretching vibration between 2053 and 2007 cm -1 . 6,[12][13][14][15][16][17][18]30,31,[33][34][35][43][44][45][46][48][49][50][51][52][53][54][55][56] Next to these, linearly bonded CO adsorbed on Rh metallic particles has been reported to give rise to a band between 2075 and 2031 cm -1 , whereas CO linearly adsorbed on oxidized Rh 1+ or Rh 2+ crystallites is attended with a band between 2135 and 2110 cm -1 . 6,12,[15][16][17]19,[32][33][34][43][44][45][46][47][48][49][50][51]53 In order to unambiguously assign...…”

Section: Resultsmentioning

confidence: 99%

Promotion Effects in the Oxidation of CO over Zeolite-Supported Rh Nanoparticles

et al. 2008

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Rh particles with an average diameter smaller than 1.5 nm have been supported on a series of zeolite Y samples. These zeolite materials contained different monovalent (H + , Na + , K + , Rb + , and Cs + ) and divalent (Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ ) cations and were used as model systems to investigate the effect of promoter elements in the oxidation of CO over supported Rh particles in excess of oxygen. Infrared (IR) spectroscopy was carried out to monitor the electronic changes in the local environment of Rh-adsorbed CO. It was found that the bands corresponding to two Rh gem-dicarbonyl species, Rh + (CO) 2 -(O z ) 2 and Rh + (CO) 2 -(O z )(H 2 O), shift to lower wavenumbers with increasing ionic radius/charge ratio of the cation. In addition, the relative intensity of the bridge bonded CO as compared to the total absorbance of Rh-bonded CO species decreases with increasing Lewis acidity, as expressed by the Kamlet-Taft parameter R of the cation. This trend could be directly correlated to the Rh CO oxidation activity, since low temperatures at 50% CO conversion corresponded with catalyst materials with a high contribution of bridge-bonded CO species and hence with small R values. A lower Lewis acidity causes an increased electron density on the framework oxygen atoms and thus an increased electron density on the zeolite-supported Rh particles. Comparable trends have been observed previously on a similar series of cation containing zeolite supported Pt catalyst materials.

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“…Similarly, on Rh C -Y zeolite a complete set of Rh C (CO) n (n D 1,2,3,4) complexes can be formed in steps upon increasing the equilibrium pressure of CO. 107 Nitrogen, NO and CO/NO mixed complexes can be formed as well in the cavities 108 so showing that the Rh C intrazeolite chemistry is very rich and diversified.…”

Section: The Vibrational Spectra Of Molecules Adsorbed On Charge Balamentioning

confidence: 98%

Vibrational Spectroscopy of Zeolites

Zecchina¹,

Spoto²,

Bordiga³

2001

Handbook of Vibrational Spectroscopy

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The sections in this article are The Structure of Zeolites and Zeotype Materials The Vibrational Spectra of Zeolites and of Zeolitic Materials: General Considerations Framework Modes IR Modes Associated with the B rØnsted Groups and their Modifications upon Interaction with Adsorbates The Spectrum of Free B rønsted Groups Modifications Induced by Adsorbates The Vibrational Spectra of Molecules Adsorbed on Charge Balancing Cations Cation and Cation‐Sensitive Modes: Perturbations Induced by Adsorption Vibrational Spectra of Molecules Adsorbed on Strong Lewis Centers Vibrational Spectroscopies in Reaction Dynamics Studies on Zeolites

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The formation of a well defined rhodium dicarbonyl in highly dealuminated rhodium-exchanged zeolite Y by interaction with CO

Cited by 83 publications

References 8 publications

A Single‐Site Platinum CO Oxidation Catalyst in Zeolite KLTL: Microscopic and Spectroscopic Determination of the Locations of the Platinum Atoms

A Single‐Site Platinum CO Oxidation Catalyst in Zeolite KLTL: Microscopic and Spectroscopic Determination of the Locations of the Platinum Atoms

Promotion Effects in the Oxidation of CO over Zeolite-Supported Rh Nanoparticles

Vibrational Spectroscopy of Zeolites

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