A Cu-Ce-Zr-O composite oxide was synthesized by microwave direct denitration (MDD) and citric acid (CA) methods, with the latter used as an experimental control. X-ray diffraction analysis confirmed that MDD facilitated the formation of a highly homogeneous Cu-Ce-Zr-O composite oxide. The specific surface area and oxygen release rate of the MDD product were 2.2-2.4 and 1.4-1.7 times larger than those of the CA product, respectively, whereas the oxygen storage capacity of the former product was slightly lower than that of the latter. Consequently, it was concluded that MDD did not significantly improve catalytic performance, although it reduced synthesis time and simplified the synthesis process. (C) 2019 Elsevier B.V. All tights reserved.