| Titre : | NO (or NH3) + O2 adsorption on fluorine-doped vanadia/titania and its role in the mechanism of a two - step process characterized by EPR (2012) |
| Auteurs : | Qin Zhong, Auteur ; Tianjiao Zhang, Auteur ; Yuntao Li, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Chemical engineering journal (Vol. 174 N° 1, Octobre 2011) |
| Article en page(s) : | pp.390–395 |
| Note générale : | Génie chimique |
| Langues : | Anglais |
| Tags : | Low-temperature selective catalytic reduction F-doping Vanadia/titania Superoxide ions |
| Résumé : |
This study aimed at elucidating a two-step process of the low-temperature selective catalytic reduction (SCR) reaction. The data were collected through studying the EPR signal of NO (or NH3) + O2 adsorption on fluorine-doped vanadia/titania and vanadia/titania catalysts used for SCR reaction, as well as the impact of SO2 and H2O added to the gas mixtures. The EPR experiments provided a new method to explain the SCR reaction, which were associated with NO (NH3) + O2 reacting systems and had been inferred step by step. In summary, the first step of the two-step process was that the vanadium sites were reduced by NO or NH3 as electron donor; then, the superoxide ions appeared over vanadium.
The experimental findings showed that the surface acidity, surface oxygen vacancies and the superoxide could be increased by fluorine doping, accordingly, the two-step process rate would be enhanced by F doping. It was the reason for F-doped catalyst had the higher catalytic activity than vanadia/titania. This two-step process could also be used to elucidate the inhibition mechanism of SO2 and H2O for the SCR reaction. |
| ISSN : | 1385-8947 |
| En ligne : | http://www.sciencedirect.com/science/article/pii/S1385894711010734 |
