Abstract: A facile route for the synthesis of nano cerium oxide powder (CeO2) is provided by the oxidation of cerium nitrate [Ce(NO3)3] with hydrogen peroxide and precipitation with ammonia. Factors influencing the size and morphology of the particle are analyzed. And the product is observed with a scanning electron microscope (SEM). Exhaust degradation test device is designed to study the photocatalytic properties of nano-CeO2 in the degradation of harmful gases within the automobile exhaust (HC and NOx). The results indicate that the ammonia concentration is 1.0 mol/L，with ethanol and ethylene glycol as dispersant，when the Ce(NO3)3 concentration is 2.0 mol/L，and the as-prepared nano-CeO2 is sphere-like nanoparticle aggregates with diameters around 50 nm and of good dispersibility，with which the degradation of HC and NOx amounts of 11% and 90% respectively，showing a good photocatalytic performance.

Key words: nanomaterial, ceria, oxidation-precipitation method, photocatalysis, exhaust degradation

摘要： 介绍了一种以双氧水氧化硝酸铈[Ce(NO3)3]，并用氨水沉淀制备纳米二氧化铈粉末（CeO2）的方法，用扫描电镜（SEM）观察了产物的颗粒形貌和粒度，分析了其制备过程中影响微观形态的因素。通过尾气降解试验装置研究了纳米CeO2对汽车尾气中的有害气体（HC、NOx）的光催化降解效能。结果表明：当Ce(NO3)3浓度为2.0 mol/L，氨水浓度为1.0 mol/L，选用乙醇和乙二醇为分散剂时，制备的球形纳米CeO2粒度在50 nm左右且分散性良好，对HC、NOx气体降解率可分别达12%和90%，具有良好的光催化性能。

关键词: 纳米材料, 二氧化铈, 氧化-沉淀法, 光催化, 尾气降解