碳化铈水解氧化法制备CeO2纳米粉

摘要

提出了一种可大规模制备CeO2纳米粉的有效方法.用碳化铈水解氧化制得颗粒大小为3～5 nm的CeO2纳米粉.研究了各种实验参数包括水解温度、反应时间和投料比对CeO2纳米粉比表面积的影响.结果表明:较低的水解温度(室温附近),较高的投料比(1∶20(g/mL))和适当的反应时间(18 h)可得到比表面积为149 m2/g的CeO2纳米粉.优化实验参数(水解温度为30℃,水解时间为18 h,投料比为1∶20(g/mL),滤饼在空气中80℃烘干4 h)得到中间产物Ce(OH)3和目标产物CeO2,并用XRD、TEM、SAED及紫外可见光分光光度计进行测试表征.发现Ce(OH)3是由大量长为50～100 nm,直径为5～20 nm的纳米棒组成.CeO2纳米粉具有较高的紫外吸收性能和较好的催化CO性能.%An effective route for the synthesis of CeO2 nanopowders on a large scale was presented. High-quality CeO2 nanopowders composed of nanoparticles with size of 3-5 nm were prepared by hydrolysis and oxidation of cerium carbide. The experimental variables which can tune the BET surface area of CeO2 nanopowders, including hydrolysis reaction temperature, reaction time, as well as feed ratio of cerium carbide, were systematically. Experimental results indicate that the lower hydrolysis temperature (around room temperature), higher feed ratio (1:20 (g/mL)), and proper reaction time (18 h) can product CeO2 nanopowders with higher surface area. The intermediate outcome Ce(OH)3 and aimed product CeO2 obtained with the optimized experimental variables (hydrolysis of cerium carbide powder at constant temperature (30'C) for 18 h in the suspension with feed ratio of 1:20 (g/mL) and dried at 80 "C for 4 h in the air) were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), selected area electron diffraction (SAED), and UY-visible absorption spectrometer. It is found that the Ce(OH)3 is composed of a large quantity of rodlike nanostructures with length of 50-100 nm and diameter of 5-20 nm and the CeO2 nanopowders have higher UV-Vis absorbance property. Furthermore, the CeO2 nanopowders possess fine CO catalytic performance.