超临界水体系制备二氧化铈纳米颗粒

Preparation of CeO_2 by Using Supercritical Water Oxidation Method

采用超临界水氧化的方法,使用自主设计的SCWO连续性反应釜制备出纳米Ce O2粉末,并应用XRD,FE-SEM,XPS等一系列分析手段对实验样品的结构与形貌进行了表征。结果表明:采用SCWO超临界反应釜制备的产物Ce O2纳米颗粒呈球形,结晶良好,平均粒径控制在10 nm左右,随着Ce(NO3)3·6H2O水溶液浓度的增大,制备出的纳米Ce O2粉末的粒径逐渐减小,粒度分布更加集中,但是粒子间团聚现象加重,Ce与O的结合能力逐渐减弱;随着Ce(NO3)3·6H2O水溶液浓度的增大,所制得的产物纳米Ce O2颗粒的BET比表面积也逐渐增加,平均比表面积为48 m2·g-1。

Supercritical water oxidation （SCWO） method was used to produce CeO2 nanopowder in this research by using self-designed SCWO continuous-type reactor. The phase composition, microstructure and morphology of ex- perimental samples were characterized by a series of analysis including X-ray diffraction, scanning electron micros- copy and X-ray photoelectron spectroscopy. The results indicate that the highly purified and good crystallinity nano- meter CeO2 powder can be obtained by SCWO method, the average particle size of nanometer CeO2 particles is con- trolled about 10 nm. The prepared particle diameter of nanometer CeO2 powder is reduced gradually along with the Ce（NO3）3 -6H20 concentration increasing, and the size distribution is more concentrated. However the higher concentration of Ce（NO3 ）3·6H20 causes serious agglomeration, and the binding capacity of Ce and O is also re- duced gradually. In addition, the BET specific surface area of the prepared products of nanometer CeOz particles increased by increasing concentration of Ce （NO3 ）3· 6H20, and the average surface area is 48 m2 ·g^- 1 .