Hydrocarbon specificity over Cu/ZSM-5 and Co/ZSM-5 catalysts in the SCR of NO
- Northwestern Univ., Evanston, IL (United States)
A large variety of catalysts has been proven to be active in the selective catalytic reduction of NO by hydrocarbons. Although O{sub 2,gas} acts as a nonselective competitor for the direct combustion of hydrocarbons, the addition of O{sub 2} enhances the rate of NO reduction. This enhancement has been attributed to the oxidation of NO which leads not to NO{sub 2, gas} but rather to adsorbed nitrogen oxide complexes (NO{sub y} groups). Although the reactivity of these NO{sub y} groups has not been fully investigated, there are literature data to suggest that the hydrocarbon must first be activated. Cant and coworkers observed a first order isotope effect when CH{sub 4} and CD{sub 4} were used as reductants. The authors concluded that H-abstraction was the rate limiting step for both N{sub 2} and CO{sub 2} formation. In general, the chemistry for the selective reduction of NO by hydrocarbons may be comparable to the chemistry of a cold flame. For these reactions, H-abstraction is the first step in hydrocarbon activation. It is therefore plausible that the NO{sub y} groups are the sites responsible for the H-abstraction reaction . The role of NO{sub y} groups on Cu/ZSM-5 and Co/ZSM-5 has been investigated by FTIR spectroscopy to determine their thermal stability and reactivity towards C{sub 3}H{sub 8} and CH{sub 4}. The nature of the evolved gases has been analyzed in separate experiments by mass spectroscopy.
- OSTI ID:
- 460144
- Report Number(s):
- CONF-950801--
- Journal Information:
- Preprints of Papers, American Chemical Society, Division of Fuel Chemistry, Journal Name: Preprints of Papers, American Chemical Society, Division of Fuel Chemistry Journal Issue: 4 Vol. 40; ISSN 0569-3772; ISSN ACFPAI
- Country of Publication:
- United States
- Language:
- English
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