CeO2 micro/nanospheres with perfect spherical morphology, large specific surface area, high porosity, high stability and adjustable diameter were hydrothermally synthesized from a simple system, and the stirring-time before hydrothermal process was found to be the key factor for the final particle size control. The CeO2 spheres with diameters from similar to 800 nm to similar to 50 nm could be harvested by controllable synthesis. And the highest specific surface area of these CeO2 spheres could achieve 182 m(2)g(-1). Moreover, CeO2 spheres with higher specific surface areas (182 m(2) g(-1) and 117 m(2) g(-1)) showed excellent performance in removal of heavy metal ion Cr(VI) from the aqueous solution. The Cr(VI) removal efficiencies could reach up to 94%. (C) 2015 Elsevier Ltd. All rights reserved.