Dual templates assisted preparation and characterization of highly thermostable multicomponent mesoporous material La–Ce–Co–Zr–O used for low-temperature CO oxidation
The multicomponent materials La–Ce–Co–Zr–O were first prepared by using mixed surfactants comprised of p-octyl polyethylene glycol phenyl ether (OP) and cetyltrimethyl-ammonium bromide (CTAB) as co-templates, which show large specific surface areas (up to 163 m2/g) and uniform pore size distributions (3.4–3.6 nm) after calcination at 500 °C. High-resolution transmission electron microscopy (HR-TEM) image shows that these materials possess wormhole-like mesoporous structures. N2 adsorption/desorption indicates that the coexistence of La and Ce in a proper atomic ratio is very crucial to improve the thermal stability of these mesoporous materials. The catalyst with La/Ce atomic ratio of 1/16 exhibits the best thermal stability. After calcination at 700 °C, its specific surface area is still up to 54 m2/g, much larger than those for the most reported LaCoO3-related perovskite. Temperature-programed reduction (H2-TPR) results show that the coexistence of La and Ce in a ratio of 1/16 can bring more profound Co–Ce interaction and the highest mobility of Co–O bond in the catalyst calcined at 700 °C. The mesoporous material La–Ce–Co–Zr–O with La/Ce atomic ratio of 1/16 exhibits not only high-thermal stability, but also novel catalytic activity for CO oxidation.
KeywordsCeO2 Co3O4 Calcination Temperature Atomic Ratio La2O3
This work is financially supported by the National Natural Science Foundation of China (No. 20676097), the “863 Program” of the Ministry of Science & Technology of China (No.2006AA06Z348), and the Program for New Century Excellent Talents in University of China (NCET-07-0599). The authors are also grateful to the support from the Natural Science Foundation of Tianjin (No.05YFJMJC09700), the Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 20040056028) and the Cheung Kong Scholar Program for Innovative Teams of the Ministry of Education (No. IRT0641).