Artifical Layer Surface of Periodic Cu-TiO2 for Catalytic Decomposition of Methanol

Article abstract of DOI:10.1021/j100318a050

Periodic thin-layer composites of Cu and TiO2 were fabricated by alternating depositions in a form of regularly distributed small spots (150 μm in diameter) in order to obtain artifically modulated catalytically active surfaces.The periodic surfaces perpendicular to the deposition direction were applied to the catalytic decomposition of CH3OH.The thickness of a Cu unit layer was changed in the range 3-10 nm, while that of the oxide support was kept at 10 nm with the total number of accumulated layers being 45.The periodic modulations of as-deposited and heat-treated composites were characterized by means of small-angle X-ray diffraction, Auger electron spectroscopy, secondary ion mass spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscope observations.It was shown that the artifical layer structures were stable upon heat treatment in vacuo and in a H2 atmosphere at high temperatures.In catalytic reaction on the Cu phases at low pressures, an interesting feature was the appearance of a maximum in the selectivity of H2CO formation at a medium thickness of the Cu layer.The effects of the periodic structures are discussed.