Characterization and catalytic performance of designed surfaces

Article abstract of DOI:10.1016/S1381-1169(00)00043-1

Designed surfaces with new and unique structures provide an opportunity to develop efficient, catalytic, molecularly organized surfaces that can lead to the ultimate catalyst technologies in the microscopic, mesoscopic, and macroscopic regions. To elucidate on these surfaces, a study investigated surface catalytic reactions assisted by gas phase molecules, which is a new aspect of catalysis on designed Co/TiO₂, Co/Al₂O₃, Co/SiO₂ surfaces. Results showed that the catalytic NO-CO reaction on the attached Co/Al₂O₃ catalyst occurred through the dinitrosyls as reaction intermediates whose conformation and amount are influenced by the gas phase CO molecules. There were no CO molecules at the catalyst surface during the reactions. The gas phase CO molecules promoted the reactivity of the dinitrosyls on the trigonally distorted tetrahedral Co²⁺ ions attached on Al₂O₃ 23 times. A new attached Mo₂/TiO₂ layer/SiO₂ catalyst was prepared by taking advantage of the reaction of Mo₂(η³-C₃H₅)₄ with surface OH groups of the TiO₂ layer followed by successive treatments with H₂ and O₂. The catalytic behavior of the Mo₂/TiO₂ layer/SiO₂ catalyst resembled that of the Mo₂/SiO₂ catalyst, but the former showed a higher activity than the latter for ethanol dehydrogenation. A new kinetic aspect of molecules on terraces and steps on a TiO₂(110)-(1x1) surface by STM was observed, which may have relevance to oxide catalysis.