CuO-ZnO/Al2 O3双功能催化剂上纤维素催化液化：焙烧温度的影响

摘要

A series of CuO-ZnO/Al2 O3 catalysts were prepared using catalyst liquefaction of cellulose in supercritical methanol which was synthesized by the co-precipitation method at various calcination temper-atures. The effect of the different calcination temperature on catalyst structure and performance was inves-tigated by using XRD,TG/DTG,BET,H2-TPR. The results showed that CuO-ZnO/Al2 O3 catalysts was al-most completely decomposed at 500 ℃. It has a good stability, activity because of the excellent proper force between CuO,ZnO and ZnAl2 O4 . Poor crystallization and stability were the reasons which lead to the decrease of the catalyst activity when the calcination temperature is less than 500 ℃. Higher calcination temperature ( >500℃) resulted in the agglomeration of CuO,generated a large number of ZnAl2 O4 make catalyst component interaction. The catalyst calcined at 500 ℃ showed good activity and stability for the repeatability test at the conditions of 300 ℃,cellulose 60 mg,60 mg catalyst,3 mL methanol and holding time 60 min.%采用共沉淀法制备了一系列不同焙烧温度用于超临界甲醇中催化液化纤维素的CuO-ZnO/Al2 O3催化剂。运用XRD、TG/DTG、BET和H2-TPR等手段对催化剂进行表征与分析,考察了焙烧温度对CuO-ZnO/Al2 O3催化剂结构及催化性能的影响。结果表明,500℃焙烧下的催化剂,热分解较为完全,CuO、ZnO和ZnAl2 O4之间相互作用良好且结构稳定,反应活性较高。当焙烧温度<500℃,催化剂结晶效果差,稳定性差,导致催化剂活性低；当焙烧温度>500℃时,CuO因为高温发生团聚,生成的大量尖晶石ZnAl2 O4使催化剂组分相互作用削弱。在300℃、60 mg微晶纤维素,60 mg催化剂,3 mL甲醇反应60 min条件下进行液化试验及重复性研究,500℃焙烧催化剂表现出良好的活性和稳定性。