[CuO-ZnO-Al_2O_3]/[HZSM-5]核壳双功能催化剂的制备、结构及其CO_2+H_2直接合成二甲醚的反应性能  

Preparation,Structure and Performance of [CuO-ZnO-Al_2 O_3]/[HZSM-5] Core-Shell Bifunctional Catalysts for One-Step Synthesis of Dimethyl Ether from CO_2+H_2

作　　者：杨晓艳[1] 孙松[1] 丁建军[1] 张义[1] 张曼曼[1] 高琛[1] 鲍骏[1] 

机构地区：[1]中国科学技术大学核科学技术学院,国家同步辐射实验室,合肥230029

出　　处：《物理化学学报》2012年第8期1957-1963,共7页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(11179034,20903084)资助项目~~

摘　　要：利用水热合成法制备了一系列不同晶化时间的核壳结构双功能催化剂[CuO-ZnO-Al2O3]/[HZSM-5], 通过X射线衍射(XRD)、扫描电镜(SEM)和能量分散谱(EDS)对催化剂结构进行了表征, 并考察了核壳催化剂CO2+H2直接合成二甲醚的反应性能. 结果表明: 通过水热合成法可在甲醇合成催化剂CuO-ZnO-Al2O3表面包覆一层完整的HZSM-5分子筛膜, 形成核壳结构, 并且调节晶化时间可以控制分子筛晶粒尺寸及膜厚. 与物理混合法制备的传统双功能催化剂相比, 核壳结构催化剂合成二甲醚的选择性显著提高, 其中晶化时间为3 d的催化剂反应性能最为理想, CO2转化率为38.9%, 二甲醚选择性达到77.0%.A series of core-shell bifunctional catalysts [CuO-ZnO-Al2O3]/[HZSM-5] for one-step synthesis of dimethyl ether from CO2 hydrogenation were prepared by a hydrothermal synthesis method, and characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. The catalyst has a core-shell structure with an integral and compact shell of HZSM-5 coated on the surface of a pre-shaped CuO-ZnO-Al2O3 pellet. The crystallite size and thickness of the zeolite shell can be controlled by the crystallization time. Compared with the mechanically mixed catalyst, the core-shell catalyst shows much higher selectivity for dimethyl ether synthesis from CO2 ＋ H2. The core-shell catalyst with a crystallization time of 3 d shows the best catalytic performance, with a CO2 conversion of 38.9% and a dimethyl ether selectivity of 77.0%.

关 键 词：核壳双功能催化剂:CO2加氢: 二甲醚:选择性 

分 类 号：TQ223.24[化学工程—有机化工]