Low-temperature NOx reduction with ethanol over Ag/Y: A comparison with Ag/γ-Al2O3 and BaNa/Y

Young Hoon Yeom, Meijun Li, Wolfgang M.H. Sachtler, Eric Weitz*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

A multistep mechanism has been elucidated for the reduction of NOx in the presence of ethanol over silver-exchanged zeolite Y (Ag/Y). Ethanol reacts with O2 and/or NO2 to form acetaldehyde at temperatures as low as 200 °C. Surface acetate ions, formed from the oxidation of acetaldehyde, react with NO2 to yield nitromethane, a critical intermediate in subsequent deNOx chemistry. CN-, NC-, and NCO- are intermediates likely bound to silver ions. Both CN- and NC- are stable toward reaction under experimental conditions. A significant difference exists between the catalytic activities of Ag/Y and Ag/γ-Al2O3; oxidation of ethanol to acetate at low temperature is significantly faster over Ag/Y than over Ag/γ-Al2O3, and both NO2 and O2 are effective oxidants over Ag/Y. With Ag/Y, pretreatment with either O2 or H2 does not affect the yield of N2, which approaches 60% and remains constant for at least 5 h, making this catalyst promising for NOx reduction.

Original languageEnglish (US)
Pages (from-to)413-427
Number of pages15
JournalJournal of Catalysis
Volume246
Issue number2
DOIs
StatePublished - Mar 10 2007

Keywords

  • Acetaldehyde
  • Acetate
  • Ethanol
  • FTIR
  • Gamma alumina
  • Kinetics
  • SCR
  • Silver
  • Zeolite Y
  • deNOx

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry

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