ZnO对CuO-ZnO/Al_2O_3催化剂催化甘油氢解性能的影响

Effect of ZnO on the Hydrogenolysis Performance of CuO-ZnO/Al_2O_3 in Catalyzing Glycerol

以氧化铝为载体,采用浸渍法制备了负载型CuO-ZnO/Al2O3催化剂,通过XRD、XPS、TPR手段表征催化剂上CuO和ZnO的分布和化学形态。结果表明,CuO-ZnO/Al2O3催化剂催化甘油氢解反应中,CuO是活性组分,ZnO的引入可以降低CuO与载体氧化铝的相互作用强度,有利于CuO的还原,提高催化剂甘油氢解活性;催化剂表面呈缺电子状态的Cu物种是甘油氢解的活性中心。当活性组分CuO质量分数为12%,n(Cu)∶n(Zn)=1∶1.5时,CuO-ZnO/Al2O3催化剂催化甘油氢解活性最高,甘油转化率可达97.82%,对1,2-丙二醇选择性达94%。

CuO-ZnO/Al2O3 catalysts supported on alumina were prepared by impregnation. XRD, XPS and TPR methods were used to characterize the distribution and chemical configuration of CuO and ZnO impregnated on the catalyst. The results show that copper oxide was the main active component, and that zinc oxide acted as a promoter in CuO-ZnO/Al2O3 catalysts. ZnO could modify the interaction between copper oxide and the supporter, which is conducive to the deoxidization of copper oxide, hence the improved hydrogenolysis performance in catalyzing glycerol. The Cu species in defect of electron was the hydrogenolysis active sites for the hydrogenolysis of glycerol. With a weight loading of 12% of CuO and Cu/Zn molar ratio of 1 ： 1.5 in the catalyst the conversion rate of glycerol was up to 97.82% , whereas the selectivity for 1,2-propanediol was nearly 94%.