Isotopic evidence for direct conversion of nitric oxide to ammonia in the absence of oxygen over vanadium pentoxide/titania and chromium(III) oxide selective catalytic reduction catalysts
| Autor: | Bronwyn L. Duffy, H. Edward Curry-Hyde, Noel W. Cant, Peter F. Nelson |
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| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry. 97:1729-1732 |
| ISSN: | 1541-5740 0022-3654 |
| DOI: | 10.1021/j100111a002 |
| Popis: | The products of the reaction between [sup 15]NO and [sup 14]NH[sub 3] over V[sub 2]O[sub 5]/TiO[sub 2]and [alpha]-Cr[sub 2]O[sub 3] catalysts in the absence of oxygen have been determined by mass spectrometry and Fourier transform infrared spectroscopy. With both catalysts [sup 14]N[sup 15]N comprises approximately two-thirds of the nitrogen-containing products. Very surprisingly, [sup 15]NH[sub 3] makes up about one-half the remainder. This has significant implications for the likely mechanism of the SCR reaction in the absence of oxygen. Formation of [sup 15]NH[sub 3] by direct exchange of both hydrogen and oxygen between [sup 14]NH[sub 3] and [sup 15]NO molecules can be ruled out since no [sup 14]NO is produced. It seems that [sup 15]NO is broken down to separate [sup 15]N and oxygen species on reduced sites and that [sup 15]NH[sub 3] can then be made by reaction of the [sup 15]N species with water. It is possible that the nitrogen-containing species is an NH group. With V[sub 2]O[sub 5]/TiO[sub 2] the only remaining product is [sup 14]N[sup 15]NO. However, this is largely replaced by doubly labeled products, [sup 14]N[sub 2], [sup 15]N[sub 2], and [sup 15]N[sub 2]O, when using [alpha]-Cr[sub 2]O[sub 3]. 22 refs., 1 fig., 2 tabs. |
| Databáze: | OpenAIRE |
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