TiO2 @Perylene Diimide Full-Spectrum Photocatalysts via Semi-Core-Shell Structure.

A semi-core-shell structure of perylene diimide (PDI) self-assembly coated with TiO2 nanoparticles is constructed, in which nanoscale porous TiO2 shell is formed and PDI self-assembly presented 1D structure. A full-spectrum photocatalyst is obtained using this structure to resolve a conundrum-TiO2 does not exhibit visible-light photocatalytic activity while PDI does not exhibit ultraviolet photocatalytic activity. Furthermore, the synergistic interaction between TiO2 and PDI enables the catalyst to improve its ultraviolet, visible-light, and full-spectrum performance. The interaction between TiO2 and PDI leads to formation of some new stacking states along the Π-Π stacking direction and, as a consequence, electron transfer from PDI to TiO2 suppresses the recombination of e- /h+ and thus improves photocatalytic performance. But the stronger interaction in the interface between TiO2 and PDI is not in favor of photocatalytic performance, which leads to rapid charge recombination due to more disordered stacking states. The study provides a theoretical direction for the study of core-shell structures with soft materials as a core, and an idea for efficient utilization of solar energy.