Abstract
The steady-state activity of NO reduction by C3H6, in lean conditions, was studied on a Pt(1%)/Ce0.6Zr0.4O2 catalyst, in a plug-flowreactor, in the temperature range 100–500 ◦C. The influence of reductive pre-treatments on the catalytic performance at low temperature(250 ◦C) was investigated. Enhancement of the activity was found for the catalyst pre-treated in hydrogen at 350 ◦C as compared to thesample pre-treated in H2 at 800 and 1050 ◦C. Moreover, transient reactivity tests of NO reduction by hydrogen were also carried out. Aspreviously observed, the sample reduced at 350 ◦C was the most active catalyst. In both types of reactions the temperature and the nature ofpre-treatments had no effect on the selectivity to N2 at the temperature of maximum NO conversion. Analyses by temperature programmedreduction (TPR), small-angle X-ray scattering (SAXS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) supported theoccurrence of a strong metal–support interaction (SMSI) effect between platinum and ceria and the important role of the platinum in promotingthe ceria-zirconia structural reorganization. Such type of interaction determined a decrease of the platinum and ceria reduction temperatureand a stabilization of the platinum oxide even in reducing atmosphere at high temperature. The catalytic behavior of the Pt/ceria-zirconiacatalyst was discussed in terms of the structural and electronic modifications induced by the SMSI effect.
Lingua originale | English |
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pagine (da-a) | 133-149 |
Numero di pagine | 17 |
Rivista | APPLIED CATALYSIS. B, ENVIRONMENTAL |
Volume | 48 |
Stato di pubblicazione | Published - 2004 |
All Science Journal Classification (ASJC) codes
- ???subjectarea.asjc.1500.1503???
- ???subjectarea.asjc.2300.2300???
- ???subjectarea.asjc.1500.1508???