In order to reduce the fraction of water and salt accessible surface OH sites on TiO2, the photocatalytic crystallites were reacted, in an HCl-releasing reaction, with a chlorine-terminated chlorinated poly(dimethylsiloxane) telomer, Glassclad 6C. When the overcoated photocatalyst was applied in the oxidation of organic films on aqueous 0.5 M NaCl, the number of O-2 molecules consumed per photon drastically increased. In the oxidation of n-octanal films, 1-25 molecules of O-2 were consumed (five electrons were transferred to oxygen), and in the oxidation of n-octanoic acid, 0.15 molecules of O-2 were consumed (0.6 electrons was transferred) per photon. The overcoating reduced the O-2-consumed/CO2-produced ratio in the initial reaction period when most of the reactant was intact. The enhancement of Oz uptake per photon and the production of oxidized organic compounds, instead of CO2, are attributed to chloride ion exclusion from the reaction zone and to fast hole oxidation, producing a radical, followed by prompt electron injection by the radical, resulting in two-electron oxidation.