Abstract:

A series of CeO2-ZrO2 complex oxides modified with K and/or Co salt were prepared and then loaded on SiC support to obtain K and/or Co-CeO2-ZrO2/ SiC catalysts by sol-gel impregnation method. The prepared catalysts were characterized by XRD, BET, H2-TPR and temperature-programmed oxidation (TPO) techniques and activity tests to investigate the effect of K and/or Co on the catalyst structure and catalytic soot combustion performance. The results show that the addition of Co increases significantly the surface oxygen activity of the catalyst for soot combustion, while the addition of K improves the contact situation between soot and catalyst, resulting in high activity for soot combustion. It is found that compared with the modified complex oxides, the catalysts all display lower soot combustion activity. The activities of the catalysts for soot combustion are in the following order: K-Co-Ce-Zr/SiC＞K-Ce-Zr/SiC＞Co-Ce-Zr/SiC＞Ce-Zr/SiC＞Co-Zr/SiC. After cycling 5 times the K-Co-Ce-Zr/SiC catalyst still shows a superior activity and high stability for soot combustion.

Key words: CeO2-ZrO2 complex oxide, SiC, soot combustion, catalytic performance