▎ 摘　　要

In this study, the relaxation dynamics of photoexcitations in anatase TiO2 nanoparticles (NPs) and their composites with metal (Au), non-metal (carbon nanotube CNT, graphene G) and combination of them (CNT-Au, G-Au) as well as its implications on the photocatalytic activities are presented. The peak positions for the steady-state photoluminescence observed at about 3 eV are invariant while the defects-related emission at visible region is blue-shifted, which depends on the nature of foreign material in the composites. Using ps time-resolved photoluminescence measurement, the decay time constants for these photoexcitations decreased with forming the composites. Concretely, the charge transfer time in TiO2 NPs is about 35.8 ps, which is longer than that in its composites, in the range of 9.7-28.7 ps. Their Raman spectra supported the plausible photodynamics of TiO2 nanocomposites that is proposed to describe the participation of photoexcitations in the photocatalytic reaction through charge separation between the different nanomaterials.