Abstract
The catalytic decomposition of NO over cobalt oxide was significantly enhanced by the addition of alkali promoters. The promotional effect was the highest with Na and the optimal Na/Co atomic ratio was 0.015. The reaction rate increased with increasing temperature up to 650°C. At 550°C, the rate measured at low conversions for the most active catalyst was 0.28 μmol N2/g s. In contrast, very low decomposition rate was observed when Na was added to ZrO2. This suggests that both Na+ and Co3O4 are necessary for the high NO decomposition activity. In 15NO temperature programmed desorption, the presence of Na in the sample resulted in the appearance of desorption peaks of NO, O2 and N2 at temperatures higher than 450°C. X-ray diffraction of a post-reaction sample detected a NaNO3 phase. It was proposed that the presence of Na facilitated the desorption of oxygen from Co3+ to form Co2+ via the formation and decomposition of NaNO3, and Co2+ was the active site for NO decomposition.
Original language | English (US) |
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Pages (from-to) | 51-60 |
Number of pages | 10 |
Journal | Catalysis Today |
Volume | 42 |
Issue number | 1-2 |
DOIs | |
State | Published - Jun 18 1998 |
Funding
This work was supported by the Petroleum Research Fund (PRF# 30177-AC5).
Keywords
- CoO
- NO decomposition
- Na promotion
- TPD
- XRD
ASJC Scopus subject areas
- Catalysis
- General Chemistry