固体酸对二氧化碳加氢合成二甲醚催化剂性能的影响

以Cu-ZnO-Al2O3催化剂作为甲醇合成组分,以不同固体酸作为脱水组分,制备了一系列CO2加氢合成二甲醚的复合催化剂。研究表明CO2的转化率与固体酸的酸性无关,而取决于Cu-ZnO-Al2O3催化剂上甲醇的合成速率;二甲醚的选择性取决于固体酸的酸量和酸强度,脱水速率与固体酸的中/强酸有关。HZSM-5分子筛作为复合催化剂脱水组分时,二甲醚的收率最高;硅铝比对CO2转化率无影响,但可显著地影响二甲醚选择性;低硅铝比的HZSM-5更适合作为CO2加氢合成二甲醚复合催化剂的脱水组分。

Effects of solid acids on hybrid catalysts for dimethyl ether synthesis from CO2 hydrogenation

Various hybrid catalysts composed of commercial CuZnO-Al_2O_3 methanol synthetic catalyst and solid acid catalysts were prepared for the production of dimethyl ether(DME) from CO_2 hydrogenation.Results show that the conversion of CO_2 is not dependent on the acidity of hybrid catalyst,but is determined by the methanol synthesis rate of hybrid catalyst.The selectivity of CO_2 to DME can be controlled by the surface acidity as well as the strength of hybrid catalyst;the middle/strong acid sites might be responsible for the formation of DME.It is also found that HZSM-5 zeolite with lower Si/Al ratio is a preferred solid acid catalyst for DME synthesis,the Si/Al ratio of HZSM-5 has little effect on the conversation of CO_2,while greatly affects the selectivity of DME.