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

doi:10.1016/j.jcat.2006.12.013

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

Research output: Contribution to journal › Article › peer-review

59 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 language	English
Pages (from-to)	413-427
Number of pages	15
Journal	Journal of Catalysis
Volume	246
Issue number	2
DOIs	https://doi.org/10.1016/j.jcat.2006.12.013
State	Published - Mar 10 2007
Externally published	Yes

Funding

This work was partially supported by the American Chemical Society Petroleum Research Fund (Grant 41855-AC5) and by the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, US Department of Energy (Grant DE-FG02-03ER15457).

Funders	Funder number
Office of Basic Energy Sciences
US Department of Energy	DE-FG02-03ER15457
Office of Science
American Chemical Society Petroleum Research Fund	41855-AC5
Chemical Sciences, Geosciences, and Biosciences Division

Keywords

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

Access to Document

10.1016/j.jcat.2006.12.013

Cite this

@article{f1961b64f71444759a2c71790425cecb,

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

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.",

keywords = "Acetaldehyde, Acetate, Ethanol, FTIR, Gamma alumina, Kinetics, SCR, Silver, Zeolite Y, deNOx",

author = "Yeom, {Young Hoon} and Meijun Li and Sachtler, {Wolfgang M.H.} and Eric Weitz",

year = "2007",

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T2 - A comparison with Ag/γ-Al2O3 and BaNa/Y

AU - Yeom, Young Hoon

AU - Li, Meijun

AU - Sachtler, Wolfgang M.H.

AU - Weitz, Eric

PY - 2007/3/10

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N2 - 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.

AB - 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.

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KW - FTIR

KW - Gamma alumina

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