CO Adsorption study of V/SiO2: the low vanadium coverage regime

Adsorption of CO and its isotopic mixtures on vanadium particles in the very low coverage growth regime (0.02–0.05 MLV) on an ultra-thin ordered silica film is monitored by IRAS at 60 K. At different CO exposures, development of different vibrational peaks was observed. These peaks are assigned to either mono- or tri-carbonyl species [V(CO)x; x=1,3] via isotopic mixture experiments. Comparing vanadium growth both on the alumina and silica films, it can be inferred from CO adsorption experiments that the metal–support interaction is weaker for vanadium growth on the silica film. The charge transfer between the vanadium metal center and the silica film is estimated based on a charge–frequency relationship to be +0.4e.