CO ADSORPTION AND HYDROGENATION ON CRYSTALLINE YBA2CU3OX THIN-FILMS

YBa2Cu3Ox (YBCO, x=6-7) is shown to have catalytic activity for methan ol synthesis from syngas in this work. In order to get more details ab out the nature of the reactive site and reaction mechanism, CO adsorpt ion and hydrogenation on a high quality YBCO thin film were studied by using in situ Fourier transform infrared spectroscopy (FTIR), angle-r esolved X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD ) and atomic force microscopy (AFM). Carbonate-like species, aldehyde, formate and methoxy were detected as reaction intermediates. After th e CO hydrogenation reaction Cu2+ ions were reduced to Cu1+, and the or thorhombic structures of YBCO was transformed to the tetragonal phase with the formation of carbonate-like complexes. The degradation of som e YBCO to amorphous surface phases was also observed. Based on these s tudies, carbonate-formate-dioxymerhylene-methoxy (or carbonate-aldehyd e-carnene-methane) reaction scheme is proposed.