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采用改进的柠檬酸溶胶-凝胶法(即前驱体先在N2气氛下高温预处理)制备了高比表面积纳米Ce0.9Cu0.1O2-δ固溶体。采用XRD、TEM和Raman等对催化剂进行表征,并考察了它们的低温CO氧化性能。研究结果表明,改进的柠檬酸溶胶-凝胶法可以制得晶相比较完整的Ce0.9Cu0.1O2-δ固溶体,晶粒小于10 nm,明显小于常规方法制得的样品。随着样品焙烧温度的提高,表征氧缺位的600 cm-1左右Raman峰的位置向高波数方向迁移。采用改进方法制得的Ce0.9Cu0.1O2-δ固溶体具有更高的CO氧化活性,其原因归结为晶粒的减小,容易形成氧缺位和表面高分散CuO的增加,从而促进了CO的氧化。
An improved citric acid sol-gel method (that is, the precursor was first pretreated at high temperature under N2 atmosphere) was used to prepare Ce0.9Cu0.1O2-δ solid solution with high specific surface area. The catalysts were characterized by XRD, TEM and Raman, and their low-temperature CO oxidation performance was investigated. The results show that the modified citric acid sol-gel method can be used to prepare Ce0.9Cu0.1O2-δ solid solution with a relatively crystalline phase with the grain size less than 10 nm, which is obviously smaller than that of the conventional method. With the increase of calcination temperature, the position of Raman peak at about 600 cm-1, which characterizes the oxygen vacancy, shifts to higher wave numbers. The Ce0.9Cu0.1O2-δ solid solution prepared by the improved method has higher CO oxidation activity, which is attributed to the decrease of the grain size, the easy formation of oxygen vacancies and the increase of surface high-dispersion CuO, thereby promoting the CO Oxidation.