Dual templates assisted preparation and characterization of highly thermostable multicomponent mesoporous material La–Ce–Co–Zr–O used for low-temperature CO oxidation

Abstract

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.