Mesoporous-shelled CeO2 hollow nanospheres synthesized by a one-pot hydrothermal route and their catalytic performance

Abstract

Uniform-sized and monodisperse CeO2 mesoporous hollow nanospheres composed of ceria nanocrystals were synthesized via a template-free and surfactant-assisted benign hydrothermal route. On the basis of a time-dependent experiment, the precipitation–dissolution–renucleation–assembly and Ostwald ripening processes mechanism is proposed for the formation of the CeO2 mesoporous hollow spheres. Poly(vinyl-pyrrolidone) (PVP) was applied as a surfactant to facilitate the reassembly of the CeO2 nanoparticles and the formation of the mesoporous shell of the hollow nanospheres. By increasing the amount of PVP, the mesoporous shell of the hollow spheres could be fabricated and became more apparent. Meanwhile, altering the amounts of H2O2 could control the size of the primary nanocrystals via affecting the nucleation/growth process of them, which is another key factor in the formation of the hollow structure and the uniform, monodispersed nanoparticles. The catalytic test results show that the as-obtained CeO2 mesoporous hollow spheres exhibited desirable CO catalytic properties. The synthesized Au–CeO2 nanospheres demonstrate a higher catalytic activity in CO oxidation than pure ceria nanospheres.