Textural, structural, and morphological characterizations and catalytic activity of nanosized CeO(2)-MO(x) (M=Mg(2+), Al(3+), Si(4+)) mixed oxides for CO oxidation

Qiang Yu; Xiaoxia Wu; Changjin Tang; Lei Qi; Bin Liu; Fei Gao; Keqin Sun; Lin Dong; Yi Chen

doi:10.1016/j.jcis.2010.10.043

Textural, structural, and morphological characterizations and catalytic activity of nanosized CeO(2)-MO(x) (M=Mg(2+), Al(3+), Si(4+)) mixed oxides for CO oxidation

J Colloid Interface Sci. 2011 Feb 1;354(1):341-52. doi: 10.1016/j.jcis.2010.10.043. Epub 2010 Oct 23.

Authors

Qiang Yu¹, Xiaoxia Wu, Changjin Tang, Lei Qi, Bin Liu, Fei Gao, Keqin Sun, Lin Dong, Yi Chen

Affiliation

¹ Key Laboratory of Mesoscopic Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.

PMID: 21074167
DOI: 10.1016/j.jcis.2010.10.043

Abstract

The present work focuses on the combination of ceria with another oxide of different ionic valences from period 3 (Mg(2+), Al(3+), and Si(4+)) using coprecipitation method, followed by calcination at 450 and 750°C, respectively. The textural, structural, morphological and redox properties of nanosized ceria-magnesia, ceria-alumina and ceria-silica mixed oxides have been investigated by means of N(2) physisorption, XRD, Raman, HRTEM, DRS, FT-IR, and H(2)-TPR technologies. XRD results of these mixed oxides reveal that only nanocrystalline ceria (ca. 3-6nm for the 450°C calcined samples) could be observed. The grain size of ceria increases with the increasing calcination temperature from 450 to 750°C due to sintering effect. The highest specific surface area is obtained at CeO(2)-Al(2)O(3) mixed oxides when calcination temperature reaches 750°C. Raman spectra display the cubic fluorite structure of ceria and the existence of oxygen vacancies, and displacement of oxygen ions from their normal lattice positions in the ceria-based mixed oxides. DRS measurements confirm that the smaller the grain size of the ceria, the higher indirect band gap energy. H(2)-TPR results suggest that the reductions of surface and bulk oxygen of ceria were predominant at low and high calcination temperature, respectively. Finally, CO oxidation were performed over these ceria-based mixed oxides, and the combination of CeO(2)-Al(2)O(3) exhibited highest activity irrespective of calcination temperature, which may due to excellent textural/structural properties, good homogeneity, and redox abilities.