New bifunctional catalyst for direct synthesis of dimethyl ether

A series Cu-ZnO-ZrO2/HZSM-5 and promoted Cu-ZnO-ZrO2/HZSM-5 catalysts, prepared by a ″coprecipitating sedimentation″ method, were used in the synthesis of dimethyl ether from hydrogenation of carbon oxides in a fixed-bed flow microreactor at a catalyst loading level of 1.0 g. Under the conditions used, with synthesis gas as reactants, the catalysts had high catalytic activities for the hydrogenation of carbon oxides and high selectivities for dimethyl ether. Among them, Mg-(Cu-ZnO-ZrO2)/V-HZSM-5 showed the best catalytic activity: 91.4% CO conversion, and 84.6% selectivity to dimethyl ether. Cu-ZnO-ZrO2/HZSM-5 gave excellent performances for CO2 hydrogenation to dimethyl ether: 35% CO2 conversion, and 60.1% selectivity to dimethyl ether. The performance of Cu-ZnO-ZrO2/HZSM-5 was affected by the reaction temperature, the suitable temperature range being 230°-250°C.