FTIR study of the electronic effects of CO adsorbed on gold nanoparticles supported on titania

Infrared spectra of CO adsorbed on nanometric gold particles supported on o xidised and reduced TiO2 are reported. Depending on which pre-treatment is used different stretching bands related to gold carbonyls have been found. On calcined samples the predominant absorption band is at 2110-2120 cm(-1), assigned to CO adsorbed linearly on nanometric gold metallic particles; on highly dehydrated, oxidised samples, a band at 2154 cm(-1) is detected, as cribed to CO adsorbed on gold oxidised sites; on reduced samples some new b ands in the frequency range 2050 to 1900 cm(-1) are produced, assigned to C O adsorbed linearly and bridge-bonded on gold small clusters, perturbed by the negative charge produced in support reduction. (C) 2000 Elsevier Scienc e B.V. All rights reserved.