{sup 15}N labeling studies of the reduction of nitric oxide by ammonia over amorphous and crystalline chromia in the presence and absence of oxygen
- Univ. of New South Wales (Australia)
- Macquarie Univ., New South Wales (Australia); and others
Isotopic labeling studies of the reaction between {sup 15}NO and {sup 14}NH{sub 3} have been performed, under selective catalytic reduction (SCR) conditions, for amorphous and crystalline chromia catalysts over a wide range of temperatures (140-350{degrees}C) and oxygen concentrations (0-1.8% O{sub 2}). At low temperatures, and with 1.8% O{sub 2}, nitrogen is formed largely by the selective reduction of NO and NH{sub 3} over both catalysts. However, crystalline chromia has a much higher activity for ammonia oxidation. Thus, at {approximately}200{degrees}C, the major form of nitrogen produced by amorphous chromia is {sup 14}N{sup 15}N, whereas, for crystalline {alpha}-Cr{sub 2}O{sub 3}, nitrogen is mainly {sup 14}N{sub 2} and is therefore produced largely from ammonia oxidation. The dominant form of nitrous oxide produced in the presence of O{sub 2} over both morphologies of chromia is always {sup 14}N{sup 15}NO. Thus, formation of N{sub 2}O, an undesirable product, involves the reaction of one molecule of NO and one molecule of NH{sub 3}. It has been shown that Fourier transform infrared (FTIR) spectroscopy can be used to distinguish between {sup 14}N{sup 15}NO and {sup 15}N{sup 14}NO.
- OSTI ID:
- 110973
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 149; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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