Electron Trapping in Colloidal TiO2 Photocatalysts: 20 ps to 10 ns Kinetics

Abstract

The trapping of excess electrons in surface sites in < 0.05 um colloidal particles of TiO2 in acid media has a time constant near 2 ns, independently of the excess electron population being produced by injection from an excited dye or hole scavenging. It is suggested that this relatively long lived state is one involved in electron transfer to solution acceptors in photocatalytic processes.