In-situ MIR-IR Observation of Peroxo Species on Anatase TiO₂ Particle during Oxygen Photoevolution Reaction

Abstract

The peroxo species on ST-01 anatase TiO₂ particles in contact with FeCl₃ aqueous solution during oxygen photoevolution were investigated by in-situ MIR-IR absorption spectroscopy. The peaks assigned to the peroxo species (TiOOH and bridging O-O) were generated by UV-irradiation, though observed vibrational energy of bridging O-O species was largely shifted from that of rutile TiO₂ particles (TIO-3). The observed difference between both particles was mainly attributable to the difference in the local surface structure of TiO₂. The existence of unknown reaction paths to consume bridging O-O species without reacting with photogenerated holes was suggested from the observation of sequential change of absorption intensity.