2D tris(triazolo)triazine-based covalent organic frameworks for efficient photoinduced molecular oxygen activation

Photoinduced molecular oxygen activation is crucial for artificial photosynthesis. However, metal-free semiconductor photocatalysts with high activation efficiency are still lacking up to now. Herein, two isomorphic tris(triazolo)triazine-based covalent organic frameworks were successfully constructed under solvothermal conditions. And they possess high crystallinity, inherent porosity with large surface area and good stability. Strong electron donor-acceptor skeletons expand the visible light harvesting, also facilitate the charge separation and thus lead to their superior activity of photoinduced molecular oxygen activation including photosynthesis of tetrahydroquinolines and hydrogen peroxide. This work provides a way to improve the efficiency of molecular oxygen activation through the rational design of COFs, and also opens new avenues for the construction of highly active and metal-free photocatalysts toward sustainable solar-to-chemical energy conversion.