Adsorption of phenol and methyl orange on the surface of TiO2 and Pt-TiO2 photocatalysts was investigated by FT-IR spectroscopy. It was found that platinum plays an important role in the adsorption properties of the studied substrates on TiO2. Platinum deposits modified the phenol-photocatalyst interaction providing new adsorption sites on TiO2 surface. On Pt-TiO2 photocatalysts, phenol mainly interacts via formation of adsorbed phenolates species. It was also found that the adsorption of methyl orange on titania and Pt-TiO2 photocatalysts occurs via interaction of the azo group with surface Ti4+. Pt photodeposition significantly increases the TiO2 photoreactivity in phenol and methyl orange photo-degradation; however, this increase depends on the properties of the Pt deposits. Moreover, it was observed that platinum content is the main factor determining the substrate-photocatalyst interaction and therefore the Pt-TiO2 photocatalytic performance. (C) 2013 Elsevier B.V. All rights reserved.