Adsorption and decomposition of Mo(CO)6 on thin Al2O3 films: fabrication of metallic molybdenum model catalyst

An ultra-thin and homogeneous alumina film is prepared by deposition and oxidation of aluminumon a platinumsubstrate under ultrahigh vacuum conditions. Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and high-resolution electron-energy-loss spectroscopy (HREELS) demonstrate that this film is completely stoichiometric and characteristic of Al2O3. Temperature-programmed desorption (TPD) and XPS characterization show that the Mo(CO)6 decomposes and leaves molybdenumwithCandOcontaminants on theAl2O3 film at 700 K. Subsequent heat treatment at 1200 Kresults in the formation of amodel surface of metallic-molybdenum-modified alumina, which could be applied to simulate the activation of CH4. # 2004 Elsevier B.V. All rights reserved