Abstract
Deactivation of singlet oxygen (1O2) by TiO2 nanoparticles was investigated for the first time. 1O2 was produced by pulse laser-induced photosensitization with either cationic or anionic porphyrin dye. Generation and decay of 1O2 were measured by its phosphorescence at 1270 nm in the presence of seven commercially available TiO2 powders of various sizes and crystallites. To clarify the quenching mechanisms, the deactivation of the triplet excited state of porphyrin dyes (3D*) with TiO2 powders was also measured by the transient T–T absorption. The Stern–Volmer plot suggests that the quenching should take place dynamically by second-order reaction. The obtained rate constants for the deactivation of 1O2 and 3D* with TiO2 were increased with the size of the particles, which is attributable to the increase of the local concentration of 1O2 and 3D* around the TiO2 particles. The intrinsic rate constant for the deactivation of 1O2 by TiO2 was elucidated to be 1.0 × 108 M–1 s–1.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
