Abstract:

YBa2Cu3Ox(YBCO, x=6-7) thin films have been prepared on the YSZ substrate and studied for CO adsorption and hydrogenation by using XPS, XRD, and in-situ FTIR. The results showed that CO adsorption occured at Cu sites and react with the oxygen species in YBCO, resulting in the formation of adsorbed CO2 or -COO bonding species and oxygen vacancies in YBCO, therefore, the Cu2+ ions of YBCO are reduced to Cu+ or Cu0, and the orthorhombic structure of YBCO is transformed to the tetragonal phase. The oxygen vacancies are in favor of adsorption of CO, CO2, and H2. The main products of CO, CO2 hydrogenation are found to be CH3OH,CH3OCH3 and a trace of CH4, and the reaction intermediates might be aldehyde, formate and methoxy radical.

Key words: YBa₂Cu₃O_x thin film, Methanol synthesis, Intermediates