Methanol Synthesis from CO2 and H2 over CuO–ZnO Catalysts Combined with Metal Oxides under 13 atm Pressure

The synthesis of methanol from CO2 and H2 in a flow reactor was studied over CuO–ZnO catalysts combined with ZrO2, MgO, Al2O3, or Cr2O3 under a presssure of 13 atm. CuO–ZnO–Al2O3, CuO–ZnO–ZrO2, and CuO–ZnO–MgO showed higher activity and higher selectivity for methanol than did CuO–ZnO. The selectivity for methanol formation became higher as the reaction temperature was lower, or any of the H2/CO2 ratio, the pressure and the space velocity were higher. On the basis of analyses by XRD, XPS, and ultraviolet diffused reflectance spectroscopy, the active centers of CuO–ZnO–ZrO2 seem to be a Cu+–ZnO species stabilized by ZrO2.