Mixing methods of the bifunctional catalyst for dimethyl ether synthesis from CO_2 hydrogenation

The bifunctional catalysts of CuO-ZnO-Al2O3/HZSM-5 for dimethyl ether synthesis from CO2 hydrogenation were prepared by suspended parallel-flow-coprecipitation,dry mixing and wet mixing methods,respectively.Effects of the preparation methods on the catalytic performance were investigated.The results showed that the coprecipitated catalyst had optimum activity,and at 270℃,3.0MPa and space velocity of 4800h-1,the one-through conversion of CO2 could reach 27.12% with the selectivity to dimethyl ether of 47.63%.The BET,XRD,TPR and TPD characterization results indicated that the introduction of HZSM-5 zeolite improved the dispersion of CuO and the specific surface area of the catalysts.Compared to pure HZSM-5,the intensity and quantity of the acidic center of the bifunctional catalysts were modified,which improved the catalytic performance of the catalysts.