Conjugated Microporous Polymers with Immobilized TiO2 Nanoparticles for Enhanced Visible Light Photocatalysis

The search for heterogeneous, visible light-active, transition metal-free, stable, and reusable photocatalysts for organic photoredox reactions remains a challenge for the chemists. Here, this study reports on a series of hybrid photocatalysts consisting of conjugated microporous polymer-based organic semiconductors with immobilized TiO2 nanoparticles. The organic/inorganic semiconductor-based hybrid photocatalytic system can enhance the photoinduced charge separation and thereby increasing the photocatalytic efficiency. As model reactions, the photocatalytic oxidative coupling reaction of amines and the selective oxidation of organic sulfides can be catalyzed with almost quantitative conversion and selectivity. The catalytic efficiency of the hybrid photocatalyst is higher than that of the pristine single photocatalytic systems as the conjugated microporous polymer and TiO2. Furthermore, the mechanistic study of the photoredox reactions is also described.