Benign synthesis of ceria hollow nanocrystals by a template-free method

Abstract

Ceria hollow nanocrystals with single-crystalline-like structure were prepared facilely by solvothermal synthesis free from templates, in which CeCl₃ was proposed to hydrolyze with the assistance of poly(vinylpyrrolidone) (PVP) in the water–ethanol mixed solvent. TEM and SEM analyses demonstrated the formation of CeO₂ hollow nanocrystals ascribed to a dissolution–recrystallization mechanism. It was found that both the counter ions of the cerium sources (e.g.CeCl₃, Ce(NO₃)₃ or (NH₄)₂Ce(NO₃)₆) and the composition of the solvent mixture were critical factors in determining the final morphology of CeO₂. The as-prepared CeO₂ hollow nanocrystals with high crystallinity exhibited a higher catalytic activity and thermal stability towards CO oxidation.