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以无水乙醇为溶剂,将Cu、Zn和Al的硝酸盐并流共沉淀在HZSM-5分子筛的悬浮溶液中,一步合成CuO-ZnO-Al2O3/HZSM-5双功能催化剂.研究了沉淀剂的种类、加入顺序和加入量对催化剂活性的影响.结果表明,以适量的草酸作沉淀剂,采用悬浮液并流共沉淀法制备的双功能催化剂,对CO2加氢直接合成二甲醚有较高的催化性能:在固定床反应器中,温度为270℃,压力为3.0 MPa,空速为4 800 h-1的反应条件下,CO2的单程转化率达到28.7%,二甲醚的选择性达到53.2%.BET、XRD、TPR、TPD和N2O滴定等对催化剂结构表征结果表明,双功能复合催化剂CuO-ZnO-Al2O3/HZSM-5的结构影响CO2加氢合成二甲醚的催化性能.
CuO-ZnO-Al2O3 / HZSM-5 bifunctional catalyst was synthesized in one step by co-precipitation of nitrate of Cu, Zn and Al in HZSM-5 molecular sieve suspension with anhydrous ethanol as solvent. Type, order of addition and amount of catalyst on the activity of the catalyst.The results show that the amount of oxalic acid as a precipitating agent, the use of suspension coprecipitation coprecipitation prepared bifunctional catalyst for the direct synthesis of dimethyl ether CO2 hydrogenation higher Under the reaction conditions of 270 ℃, pressure of 3.0 MPa and space velocity of 4 800 h-1 in a fixed-bed reactor, the single-pass conversion rate of CO2 reached 28.7% and the selectivity of dimethyl ether reached 53.2% .The results of BET, XRD, TPR, TPD and N2O titration indicate that the structure of CuO-ZnO-Al2O3 / HZSM-5 catalyst affects the catalytic performance of dimethyl ether (DME)