Development of Cu/ZnO/Al2O3 catalyst for dimethyl ether synthesis from CO-CO2-H2 mixture

The objective of this study is to develop a catalyst for direct synthesis of dimethyl ether ((CH3)(2)O, DME) from a CO-CO2-H-2 mixture such as blast furnace gas. For this purpose, precipitated Cu-ZnO-X (X=Al2O3, Cr2O3, ZrO2 or Ga2O3) were systematically prepared by changing chemical composition and their catalytic activity was measured. For Cu-ZnO-Al2O3 catalyst, compositional research was on two parameters, namely Cu/ZnO ratio (3/7-5/5) and content of Al2O3 (0-33.0 mol%). The influence of each parameter was estimated by DME and MeOH yields for the same catalyst mass. Some Cu-ZnO-Al2O3 catalysts synthesized DME more than MeOH, in which the DME activity was related to specific surface area and existence of broadened ZnO peaks in XRD patterns. In contrast, three other Cu-ZnO catalysts including another oxide (Cr2O3, ZrO2 or Ga2O3) synthesized only MeOH without DME. Content of Al2O3 was more influential on DME synthesis than Cu/ZnO ratio. In conclusion, the most active composition of Cu-ZnO-Al2O3 catalyst for DME synthesis was Cu/ZnO = 4/6 with 14.3 mol% Al2O3 and interestingly this composition was included within the range of usual MeOH synthesis catalysts.