Decomposition of NO over [Co]-ZSM-5 zeolite: Effect of co-adsorbed O{sub 2}
- ABB Lummus Global, Inc., Bloomfield, NJ (United States)
- Catalytica, Inc., Mountain View, CA (United States)
The decomposition of NO over four Co-containing ZSM-5 zeolites and Pr, Ga-, and Cu-exchanged ZSM-5 zeolites was investigated using the isotope labeled {sup 15}N{sup 18}O and a temperature-programmed desorption (TPD) technique. The authors found that [Co]-ZSM-5 that contains Co in the framework had the highest activity for NO decomposition, almost an order of magnitude greater than that previously reported for a zeolite catalyst, namely Cu-ZSM-5 obtained under steady-state conditions. The phenomenally high activity of [Co]-ZSM-5 is due to the unique incorporation of Co{sup 2+} in the siliceous MFI structure. For all the catalysts investigated, co-adsorption of NO and O{sub 2} led to a substantial increase in the amount of NO{sub x} adsorbed. However, the adsorbed species were not necessarily NO{sub 2} as reported by others. The authors believe that the interaction between adsorbed NO{sub x} species and O{sub 2} is responsible for enhancing the rate of NO{sub x} decomposition. It is obvious that the framework Co{sup 2+} behaves very differently from Co{sup 2+} in the countercation position and from extra-framework CoO such as that supported on or dispersed on the surface of silicalite also having the same MFI structure.
- OSTI ID:
- 659084
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 2 Vol. 178; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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