ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Promotional effect of cobalt addition on catalytic performance of Ce0.5Zr0.5O2 mixed oxide for diesel soot combustion
Yan-Hua Zhang, Hai-Long Zhang, Yi Cao, Yi Yang, Bao-Qiang Xu, Ming Zhao, Mao-Chu Gong, Hai-Di Xu, and Yao-Qiang Chen
Key Laboratory of Green Chemistry and Technology of the Ministry of Education, College of Chemistry
Abstract: A series of Co-modified Ce0.5Zr0.5O2 catalysts with different concentrations of Co (mass %: 0, 2, 4, 6, 8, 10) was investigated for diesel soot combustion. Ce0.5Zr0.5O2 was prepared using the co-precipitation method and Co was loaded onto the oxide using the incipient wetness impregnation method. The activities of the catalysts were evaluated by thermogravimetric (TG) analysis and temperature-programmed oxidation (TPO) experiments. The results showed the soot combustion activities of the catalysts to be effectively improved by the addition of Co, 6 % Co/Ce0.5Zr0.5O2 and that the 8 % Co/Ce0.5Zr0.5O2 catalysts exhibited the best catalytic performance in terms of lower soot ignition temperature (Ti at 349 °C) and maximal soot oxidation rate temperature (Tm at 358 °C). The reasons for the improved activity were investigated by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), H2 temperature-programmed reduction (H2-TPR), X-ray photo-electron spectroscopy (XPS) and transmission electron microscopy (TEM). These results revealed that the presence of Co could lower the reduction temperature due to the synergistic effect between Co and Ce, thereby improving the activity of the catalysts in soot combustion. The 6 % Co catalyst exhibited the best catalytic performance, which could be attributed to the greater amounts of Co3+ and surface oxygen species on the catalyst.
Keywords: Co3O4 – Ce0.5Zr0.5O2 – catalytic performance – diesel soot combustion
Full paper is available at www.springerlink.com.
Chemical Papers 70 (10) 1370–1379 (2016)