溶胶凝胶法制备La_2O_3/AAO纳米阵列及其催化性能

Preparation and Catalytic Properties of La_2O_3/AAO Nanoarrays by Sol-gel Method

通过溶胶凝胶法与阳极氧化铝模板法(AAO)相结合来可控合成La_2O_3/AAO纳米阵列催化剂,以丙酮缩合制备二丙酮醇为探针反应考察了催化剂的催化性能。采用XRD、SEM、TEM、BET和CO2-TPD对催化剂进行了表征。结果表明,催化剂活性组分La_2O_3在AAO模板上分散均匀,当焙烧温度为900℃,焙烧时间为1 h时,反应时间3 h,催化剂活性达到最佳,此时丙酮转化率为4.01%,二丙酮醇选择性为96.32%。催化剂重复使用5次后,丙酮转化率为3.63%,二丙酮醇选择性为97.06%。La_2O_3/AAO-900催化剂具有较大的比表面积和较强的弱碱性位是其活性高的主要原因。

La2O3/ AAO nanoarrays catalysts were controllable prepared with anodic aluminum oxide（ AAO） template by sol-gel method,and catalytic activity of the catalyst was tested using aldol condensation of acetone to diacetone alcohol as a probe reaction. The catalysts were characterized by XRD,SEM,TEM,BET and CO2-TPD. The results showed that La2O3 were highly and homogeneously dispersed on the AAO surface. When the calcination temperature was 900 ℃,calcination time was 1hour and the reaction time was 3 h,La2O3/ AAO-900 catalyst showed the highest catalytic activity which the conversion of acetone was 4. 01% and the selectivity to diacetone alcohol was 96. 32%. The conversion of acetone was 3. 63% and the selectivity to diacetone alcohol was 97. 06% after 5 runs.The higher catalytic performance of La2O3/ AAO-900 catalyst is attributed to its larger specific surface area,weak basic sits and a large basic amounts.