One-electron oxidation of aromatic sulfides adsorbed on the surface of TiO2 particles studied by time-resolved diffuse reflectance spectroscopy

One-electron oxidation of 4-methyl-p-tolylsulfide (MTS) and 4-methylthiophenylmethanol (MTPM) adsorbed on the surface of TiO2 powder slurried in acetonitrile has been investigated by the time-resolved diffuse reflectance spectroscopy. Relatively high concentration of the adsorbed MTPM determined by UV absorption spectral measurements clearly indicates that the –OH group of MTPM plays an important role in adsorbing on the surface of TiO2 particles. The initial concentration of the radical cations of substrates generated from one-electron oxidation with valence band holes or trapped hydroxyl radical significantly depended on the substrate concentration adsorbed on the TiO2 surface.