CeO(2) Structure Adjustment by H(2)O via the Microwave–Ultrasonic Method and Its Application in Imine Catalysis

CeO(2) with fusiform structures were prepared by the combined microwave–ultrasonic method, and their morphologies and surface structure were changed by simply adding different amounts of H(2)O (1–5 ml) to the precursor system. The addition of H(2)O changed the PVP micelle structure and the surface state, resulting in CeO(2) with a different specific surface area (64–111 m(2) g(−1)) and Ce(3+) defects (16.5%–28.1%). The sample with 2 ml H(2)O exhibited a high surface area (111.3 m(2)∙g(−1)) and relatively more surface defects (Ce(3+)%: 28.1%), resulting in excellent catalytic activity (4.34 mmol g(−1) h(−1)).