二氧化碳加氢直接合成二甲醚催化剂的研究 Ⅰ. 沉淀剂对催化剂结构和性能的影响

STUDY ON DIRECT SYNTHESIS OF DIMETHYL ETHER BY HYDROGENATION OF CARBON DIOXIDEⅠ. EFFECTS OF PRECIPITATION AGENT ON STRUCTURE AND PROPERTIES OF CATALYST

使用不同沉淀剂制备了CuO ZnO Al2O3 HZSM 5复合型催化剂,考察了其对CO2直接加氢的催化性能,并采用H2 TPR、XRD、BET、CO2 TPD、H2 TPD等表征方法对催化剂物化性质进行了表征。研究结果表明,沉淀剂对催化剂的反应性能、晶相结构、还原难易程度、以及对CO2、H2的吸附性能等均有显著影响。催化剂上存在两种吸附位,催化剂的活性、选择性与其吸附性能密切相关。研究结果可以较好地解释CO2直接转化为甲醇和二甲醚的反应机理。

A series of CuOZnOAl2O3/HZSM5 composed catalysts were prepared with different precipitation agents, such as aqueous solution of ammonia, sodium hydroxide, sodium oxalate and sodium carbonate Their catalytic performance for hydrogenation of CO2 was evaluated The physicalchemical properties of the catalysts were also studied by means of H2TPR, XRD, BET, CO2TPD and H2TPD The result showed that precipitation agents had obvious effect on the activity, structure of crystal phases, reduction property, as well as absorption properties to CO2 and H2 of catalyst There existed two kinds of adsorption center on the catalyst. Their activity and selectivity were in close relationship with the adsorption property The mechanism of CO2 hydrogenated directly to methanol and DME were proposed based on the study