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 oxidised 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, ascribed to CO adsorbed on gold oxidised sites; on reduced samples some new bands in the frequency range 2050 to 1900 cm−1 are produced, assigned to CO adsorbed linearly and bridge-bonded on gold small clusters, perturbed by the negative charge produced in support reduction.