SiO_2助剂对CuO-ZnO/HZSM-5催化CO_2加氢制DME性能的影响

采用均匀沉淀法制备了不同SiO_2含量的CuO-ZnO作为CO_2加氢合成甲醇的活性组分,接着采用研磨法将其与HZSM-5分子筛均匀混合形成双功能催化剂,考察了不同SiO_2含量催化剂在CO_2加氢合成二甲醚反应中的催化性能.通过XRD、N_2等温吸附脱附、H_2-TPR、NH_3-TPD、N_2O滴定对催化剂结构进行表征,研究了SiO_2含量对催化剂结构及表面酸性的影响.结构表征表明助剂SiO_2的加入增加了催化剂的比表面积,提高了催化剂的还原性,使催化剂的表面酸性较为合适,同时在一定程度上能够抑制催化剂活性组分的聚集,从而有效促进了催化剂的催化活性.

Effect of SiO2 Promoter on Performance of CuO-ZnO /HZSM-5 Catalysts for Synthesis of DME from CO2 Hydrogenation

A series of CuO-ZnO catalysts with various SiO2 content were synthesized by homogeneous precipitation method,then mixed with HZSM-5 zeolite by grinding method and form a bifunctional catalyst.The catalytic per-formances of catalysts for the synthesis of dimethyl ether from CO2 hydrogenation were tested.XRD,N2 isothermal adsorption-desorption,H2-TPR and NH3-TPD and N2 O titration were employed to investigate the structure of the catalyst.The effect of SiO2 content on the structure and surface acidity of the catalyst was studied.The result showed that the addition of promoter SiO2 increased the specific surface area and improved the reduction ability,in addition,aggregation of the active components can be decreased,thus promoting the catalytic activity.