Temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS) have been employed to study the adsorption and photon-induced decomposition of Mo(CO)6. Mo(CO)6 adsorbs molecularly on a Pt(111) surface with weak interaction at 100 K and desorbs intact at 210 K without undergoing thermal decomposition. Adsorbed Mo(CO)6 undergoes decarbonylation to form surface Mo(CO)x (x ≤ 5) under irradiation of ultraviolet light. The Mo(CO)x species can release further CO ligands to form Mo adatoms with CO desorption at 285 K. In addition, a fraction of the released CO ligands transfers onto the Pt surface and subsequently desorbs at 350-550 K. The resulting Mo layer deposited on the Pt surface is nearly free of contamination by C and O. The deposited Mo adatoms can diffuse into the bulk Pt at temperatures above 1070 K.
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