The cerium-zirconium composite oxide and its manufacture and the use of catalyst ·

Provided are a cerium-zirconium composite oxide, a preparation method therefor and application of a catalyst. The cerium-zirconium composite oxide has a composite phase structure, and comprises a cerium oxide phase and a cerium-zirconium solid solution phase, or consists of two or more cerium-zirconium solid solution phases with different crystal structures and different chemical compositions, wherein the chemical formula of the cerium-zirconium solid solution phase is Ce x Zr 1-x-y M y O 2 , where M is at least one selected from the group consisting of a rare earth element other than cerium, a transition metal element and an alkaline earth metal element, x is 15-85 mol%, and y is 0-20 mol%. Due to the presence of two or more phases, the cerium-zirconium composite oxide has a relatively high high-temperature resistance and specific surface area, so that a catalyst prepared from the composite oxide has a good catalytic performance.