Adsorption of acetonitrile and its reaction with oxygen on TiO 2-supported Au - Rh bimetallic catalysts

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Abstract

The adsorption of acetonitrile and its surface reactions with oxygen on TiO2-supported Au - Rh bimetallic catalysts were studied by FTIR and mass spectrometry at 300-673 K. The band due to CH3CN on Lewis acid centres shifted to lower wavenumbers with the increase of the Rh content, which shows that the strength of Lewis acid sites weakens with the increase of the Rh content of the catalysts. CH3CN, on the other hand, dissociates producing CN(a) species. From the shift to higher wavenumbers of the band due to CN(a), strengthening of the C - N bond with increasing Rh content has been established. During the heat treatments of the adsorbed CH3CN layer, methylamine (CH3NH2) was detected in the gas phase, the amount of which depended on the composition of the catalysts. Dehydrogenation of the adsorbed acetonitrile also depends on the Rh content: the higher the Rh content of the sample, the lower the temperature of the first appearance of gaseous H2, and the higher the amount of H2 evolved. The presence of gaseous oxygen affects the formation of isocyanate (NCO) surface species only on 1% Au/TiO2 and on 1% (0.75Au-0.25Rh)/TiO2 catalysts.

Original languageEnglish
Pages (from-to)149-160
Number of pages12
JournalReaction Kinetics and Catalysis Letters
Volume91
Issue number1
DOIs
Publication statusPublished - Jun 2007

Fingerprint

Acetonitrile
acetonitrile
Oxygen
Adsorption
catalysts
Lewis Acids
Catalysts
adsorption
oxygen
Isocyanates
Acids
Surface reactions
Dehydrogenation
acids
isocyanates
Mass spectrometry
dehydrogenation
Gases
Heat treatment
surface reactions

Keywords

  • Acetonitrile adsorption
  • Dissociation and dehydrogenation of acetonitrile
  • NCO formation

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Catalysis

Cite this

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title = "Adsorption of acetonitrile and its reaction with oxygen on TiO 2-supported Au - Rh bimetallic catalysts",
abstract = "The adsorption of acetonitrile and its surface reactions with oxygen on TiO2-supported Au - Rh bimetallic catalysts were studied by FTIR and mass spectrometry at 300-673 K. The band due to CH3CN on Lewis acid centres shifted to lower wavenumbers with the increase of the Rh content, which shows that the strength of Lewis acid sites weakens with the increase of the Rh content of the catalysts. CH3CN, on the other hand, dissociates producing CN(a) species. From the shift to higher wavenumbers of the band due to CN(a), strengthening of the C - N bond with increasing Rh content has been established. During the heat treatments of the adsorbed CH3CN layer, methylamine (CH3NH2) was detected in the gas phase, the amount of which depended on the composition of the catalysts. Dehydrogenation of the adsorbed acetonitrile also depends on the Rh content: the higher the Rh content of the sample, the lower the temperature of the first appearance of gaseous H2, and the higher the amount of H2 evolved. The presence of gaseous oxygen affects the formation of isocyanate (NCO) surface species only on 1{\%} Au/TiO2 and on 1{\%} (0.75Au-0.25Rh)/TiO2 catalysts.",
keywords = "Acetonitrile adsorption, Dissociation and dehydrogenation of acetonitrile, NCO formation",
author = "J. Rask{\'o} and J. Kiss",
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language = "English",
volume = "91",
pages = "149--160",
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T1 - Adsorption of acetonitrile and its reaction with oxygen on TiO 2-supported Au - Rh bimetallic catalysts

AU - Raskó, J.

AU - Kiss, J.

PY - 2007/6

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N2 - The adsorption of acetonitrile and its surface reactions with oxygen on TiO2-supported Au - Rh bimetallic catalysts were studied by FTIR and mass spectrometry at 300-673 K. The band due to CH3CN on Lewis acid centres shifted to lower wavenumbers with the increase of the Rh content, which shows that the strength of Lewis acid sites weakens with the increase of the Rh content of the catalysts. CH3CN, on the other hand, dissociates producing CN(a) species. From the shift to higher wavenumbers of the band due to CN(a), strengthening of the C - N bond with increasing Rh content has been established. During the heat treatments of the adsorbed CH3CN layer, methylamine (CH3NH2) was detected in the gas phase, the amount of which depended on the composition of the catalysts. Dehydrogenation of the adsorbed acetonitrile also depends on the Rh content: the higher the Rh content of the sample, the lower the temperature of the first appearance of gaseous H2, and the higher the amount of H2 evolved. The presence of gaseous oxygen affects the formation of isocyanate (NCO) surface species only on 1% Au/TiO2 and on 1% (0.75Au-0.25Rh)/TiO2 catalysts.

AB - The adsorption of acetonitrile and its surface reactions with oxygen on TiO2-supported Au - Rh bimetallic catalysts were studied by FTIR and mass spectrometry at 300-673 K. The band due to CH3CN on Lewis acid centres shifted to lower wavenumbers with the increase of the Rh content, which shows that the strength of Lewis acid sites weakens with the increase of the Rh content of the catalysts. CH3CN, on the other hand, dissociates producing CN(a) species. From the shift to higher wavenumbers of the band due to CN(a), strengthening of the C - N bond with increasing Rh content has been established. During the heat treatments of the adsorbed CH3CN layer, methylamine (CH3NH2) was detected in the gas phase, the amount of which depended on the composition of the catalysts. Dehydrogenation of the adsorbed acetonitrile also depends on the Rh content: the higher the Rh content of the sample, the lower the temperature of the first appearance of gaseous H2, and the higher the amount of H2 evolved. The presence of gaseous oxygen affects the formation of isocyanate (NCO) surface species only on 1% Au/TiO2 and on 1% (0.75Au-0.25Rh)/TiO2 catalysts.

KW - Acetonitrile adsorption

KW - Dissociation and dehydrogenation of acetonitrile

KW - NCO formation

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