Acetylene hydrogenation on SiO2 supported gold nanoparticles

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19 Citations (Scopus)

Abstract

Acetylene hydrogenation has been investigated on 1.8 wt.% Au(I)/SiO 2 and 1.9wt.% Au(II)/SiO2 catalysts prepared by fixation of Au sol to SiO2 (Aerosil 200). The mean particle size measured by TEM is 3.7 and 6.1 nm, respectively. For the sake of comparison a 2.1 wt.% Au/TiO2 sample was prepared by deposition-precipitation (DP) technique (mean particle size of Au is 3.3 nm). Transformation of acetylene was measured at 5 K/min ramp rate with gas mixtures containing the reactants at H2/C2H2=2 and 70 ratios. The C 2H2 content of the gas mixture was 0.11% (0.11 kPa C 2H2). The activity sequence at 423 K was: Au/TiO 2>Au(I)/SiO2≥Au(II)/SiO2. Both the partial pressure of hydrogen and the temperature significantly affect the activity (acetylene conversion) and ethylene selectivity. Above 500-550 K over-hydrogenation (ethane formation) and hydrogenolysis (methane formation) decrease the ethylene selectivity. Faster deactivation and larger amount of deposit was observed on Au/TiO2 than on Au(I)/SiO2. A reaction scheme is proposed suggesting formation of sigma bonded intermediates as sp carbon hybridises to sp2 and sp3.

Original languageEnglish
Pages (from-to)43-54
Number of pages12
JournalReaction Kinetics and Catalysis Letters
Volume96
Issue number1
DOIs
Publication statusPublished - Feb 1 2009

Keywords

  • Acetylene hydrogenation
  • Au catalyst
  • Au particle size
  • Selectivity
  • TPO measurement

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry

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