The synthesis of methanol from CO/CO₂/H₂ gas over Cu/Ce_1-xZr_xO₂ catalysts

In this study, we investigated the catalysis of Cu/Ce_1-xZr _xO₂ for the synthesis of methanol from CO/CO ₂/H₂ gas. The Ce_1-xZr_xO₂ was synthesized by a surfactant (CTAB)-assisted co-precipitation method to yield high surface area supports, and Cu was deposited on the supports by a deposition-precipitation method to promote high Cu dispersion. The incorporation of Zr into the CeO₂ lattice transformed the structure into a defective, pseudo-cubic one and the amount of incorporated Zr (x) determined the concentration of oxygen vacancy in the lattice. It was proposed that the oxygen vacancy in Ce_1-xZr_xO₂ played an important role in the catalysis by determining concentration and mobility of the adsorbed CO_x on the catalyst. The activity was also influenced by the exposed surface area of Cu and surface acidity of the catalyst, both of which were closely related to the amount of Zr in the support. To reveal the influences of the catalyst properties on methanol production, various characterization techniques were used, such as XPS, Raman spectroscopy, XRD, H₂-TPR, NH₃-TPD, BET and N₂O titration methods.