The effect of illumination on the activation and dissociation of CO2 was investigated at 190 and 300 K on titania-supported noble metals by means of Fourier transform infrared spectroscopy. The photoinduced dissociation of CO2 (through the formation of CO2(a)(-)) resulting in CO(a) occurred on Pt/TiO2, Rh/TiO2 and Ir/TiO2; no CO(a) formation, however, was observed on Pd/TiO2 and Ru/TiO2. It is assumed that the CO2 on supported noble metals is bonded to the surface with both C (linked to a noble metal atom) and one of the O atoms (linked to the oxygen vacancy of the supports), and an extended charge transfer induced by illumination leads to the cleavage of a C-O bond.