Controllable synthesis and properties of nano-CeO2

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Nano-CeO2 catalysts with different shapes were synthesized at different hydrothermal temperatures. The physical and chemical properties of the synthesized nano-CeO2 catalysts were characterized using XRD, TEM, XPS, O2-TPD, and H2-TPR. The catalytic properties of the prepared nano-CeO2 catalysts for the catalytic oxidation of ethanol in air were also investigated. The synthesized nano-CeO2 catalysts display similar cubic fluorite structures and different crystallinities. The CeO2 nanorods are synthesized at a hydrothermal crystallization temperature of 80–120 °C and that CeO2 with a mixed structure of nanorods and nanocubes is synthesized at 140 °C. The CeO2 nanorod and nanocube catalysts exhibit different reduction behaviors toward H2 and that the CeO2 nanorod catalyst performs better than the CeO2 nanocube catalyst in low-temperature reduction. The results of ethanol catalytic oxidation show that the prepared CeO2 nanorod and nanocube catalysts yield oxidation and dehydration products (including ethylene, acetaldehyde, acetic acid, CO2, and trace acetic ether). The CeO2 nanorod catalyst synthesized at 100 °C exhibits a high ethanol oxidation conversion exceeding 99.2% at 170 °C and a CO2 selectivity exceeding 99.5% at 210 °C. However, the ethanol oxidation conversion of this catalyst can reach 95.4% until 235 °C, and its CO2 selectivity is only 91.83% at 270 °C. The research work is of great significance for the controllable synthesis of nano-oxide materials and the removal of OVOCs from air.