CuO/cryptomelane catalyst for preferential oxidation of CO in the presence of H 2 : deactivation and regeneration
Cryptomelane and CuO/cryptomelane catalysts have been tested in the preferential oxidation of CO in the presence of H 2 (CO-PROX reaction), paying special attention to deactivation and regeneration issues. Cryptomelane was stable during the CO-PROX reactions in ramp experiments until 200 °C and in a...
Saved in:
Published in | Catalysis science & technology Vol. 6; no. 14; pp. 5684 - 5692 |
---|---|
Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
2016
|
Online Access | Get full text |
Cover
Loading…
Summary: | Cryptomelane and CuO/cryptomelane catalysts have been tested in the preferential oxidation of CO in the presence of H
2
(CO-PROX reaction), paying special attention to deactivation and regeneration issues. Cryptomelane was stable during the CO-PROX reactions in ramp experiments until 200 °C and in a long-term isothermal experiment (10 h). Changes neither in the H
2
reducibility and porosity nor in the crystalline phases detected by XRD were observed. On the contrary, CuO/cryptomelane was partially deactivated during the consecutive CO-PROX reaction cycles performed until 200 °C, and the catalytic activity was partially restored by reoxidising the catalyst at 200 °C or 400 °C, the latter temperature being more effective. In spite of the CuO/cryptomelane partial deactivation, the CO-PROX activity of this catalyst was higher than that of cryptomelane once a stable behaviour was achieved. The partial deactivation of CuO/cryptomelane was attributed to the segregation of crystalline phases (hausmannite (Mn
3
O
4
) and/or hopcalite (CuMn
2
O
4
)), with the segregation of potassium to the surface and decrease in the copper cations' reducibility. The potential contribution to deactivation of the changes in the porous texture of CuO/cryptomelane was ruled out. |
---|---|
ISSN: | 2044-4753 2044-4761 |
DOI: | 10.1039/C6CY00329J |