In this study, we have explored commercial ceria, commercial cobalt oxide (Co3O4) and a laboratory synthesized nano-ceria supported cobalt oxide (Co3O4) for catalytic NO oxidation, which is an important reaction for soot oxidation in diesel particulate filters (DPF), used for vehicle exhaust emissions control. Ceria supported cobalt oxide has been synthesized by incipient wetness impregnation method, and shows high catalytic activity for NO oxidation at moderate temperature. The catalytic activity is even comparable to reported noble metal based NO oxidation catalysts, and could be mainly due to the high dispersion of Co3O4 nanoparticles on ceria support with enhanced catalyst support interaction. This has also resulted in improved redox properties of Co3O4-ceria catalyst. (C) 2014 Elsevier B.V. All rights reserved.