Characterization of some perovskite oxides based on YBa2Cu3O7 − x in relation to their use in methanol production

The oxidized and weakly reducible perovskite oxide YBa₂Cu₃O_{7 − x} (YBCO) has been prepared as a catalyst, supported on γ‐Al₂O₃. It was further modified by (i) impregnation with Ru and Pd and (ii) cobalt incorporation via co‐precipitation. All the catalysts were either 20% (w/w) YBCO/γ‐Al₂O₃ or 2% (w/w) Ru, Pd or Co/20% (w/w) YBCO/γ‐Al₂O₃. The catalysts were characterized using temperature programmed reduction (TPR), surface area measurements and X‐ray diffraction (XRD) studies before and after various treatments. They were studied as catalysts in the pressure range 20–50 atmospheres and in the temperature range 523–573 K in an autoclave equipped with a spinning basket catalyst container. The Pd‐, Ru‐ and Co‐modified catalysts gave predominantly methanation products, along with some C₂–C₄ hydrocarbons. However the YBCO/γ‐Al₂O₃ catalyst exhibited significant methanol selectivity at 50 atmospheres and at 523 K X‐ray diffraction studies revealed the presence of Cu(0), Cu(I) and Cu(II) after reduction and the species Cu(0) and Cu(I) are probably essential to CH₃OH production. © 2000 Society of Chemical Industry