Preparation of CuO-ZnO-ZrO_2/HZSM-5 Catalysts for Synthesis of Dimethyl Ether by Solid Grinding-Combustion Method

Cu-ZnO-ZrO2/ HZSM-5 bifunctional catalysts for dimethyl ether synthesis from hydrogenation of CO2were prepared by solid grinding-burning and mechanical mixing method. The catalyst performance of the catalyst in the hydrogenation were investigated,at reaction temperature 270 ℃,pressure of 3. 0 MPa,space velocity 4 200 h- 1o ver a fixed-bed reactor. This article focuses on the effects of the amount of citric acid added on the catalyst structure and performance. Experimental results showed that dimethyl ether selectivity and yield first increased and then decreased with the increase of citric acid,the maximum catalytic activity was obtained from the catalyst prepared with the stoichiometric amount of citric acid. The one way conversion of CO2was 24. 8%,the selectivity and the yield of dimethyl ether were 35. 3% and 8. 7% respectively. XRD,BET,H2-TPR,NH3-TPD,XPS characterization results showed that the amount of citric acid added could influence the catalyst surface area,distribution of copper,reduction performance,consequently the catalytic performance was affected by those parameters.