Hierarchical Organization and Catalytic Activity of High-Surface-Area Mesoporous Ceria Microspheres Prepared Via Hydrothermal Routes

Mesoporous Ce(OH)CO3 microspheres with flowerlike three-dimensional (3D) hierarchical structure were successfully synthesized via different hydrothermal systems, including glucose/acrylic acid, fructose/acrylic acid, glucose/propanoic acid, and glucose/n-butylamine systems. After Ce(OH)CO3 microspheres were calcined, mesoporous CeO2 microspheres with the same flowerlike morphology as Ce(OH)CO3 microspheres were obtained. Especially, flowerlike CeO2 microspheres prepared via the glucose/acrylic acid system are composed of many interconnected mesoporous petal-like nanosheets with thicknesses of 40−60 nm and have high surface area (211 m2 g−1), large pore volume (0.32 cm3 g−1), and narrow pore size distribution (∼3.8 nm in diameter). A possible formation mechanism of Ce(OH)CO3 microspheres is proposed: the large N-containing organic compounds in situ produced in the above reaction systems played a crucial role in controlling the assembly of Ce(OH)CO3 building blocks into the flowerlike Ce(OH)CO3 microspheres. For trichloroethylene combustion, flowerlike CeO2 microspheres were found to exhibit much higher catalytic activity than general CeO2 prepared with the conventional methods and the T10% and T90% were as low as 100 and 204 °C, respectively.