The present work comparatively explored the morphology and size-dependent reduction and activity of CeO(2) nanostructures for NO reduction. CeO(2) nanorods were prepared by Ce(NO(3))(3), while spherical-like nanoparticles with an average size of 4-6 nm were obtained from (NH(4))(2)Ce(NO(3))(6) and Ce(SO(4))(2). As compared with CeO(2) nanorods, these nanoparticles (4-6 nm) showed the larger lattice strain and higher activity for NO reduction, which was due to the nanosize effect that significantly improved the intrinsic reducibility of surface oxygen and facilitated the formation of oxygen vacancies. In addition, the adsorption type and configuration of NO was similar over these different shaped ceria. However, CeO(2) nanoparticles from tetravalent cerium showed the greater capacity to activate the adsorbed NO species than nanorods from the tervalent nitrates. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.