Covalent triazine frameworks with Ru molecular catalyst for efficient photocatalytic oxygen evolution reaction

The development of efficient oxygen evolution reaction (OER) photocatalysts to enable solar-driven photocatalytic water splitting into oxygen has been tremendously challenging, primarily due to the low oxygen evolution efficiency caused by intrinsically sluggish kinetics. Herein, we report the design of a novel “host-guest” photocatalytic system that incorporates the molecular ruthenium (Ru) catalyst into covalent triazine framework (CTF) channels through a facile immersion treatment. The CTF acts as the photosensitizer and support material, while the mononuclear Ru-based complex Ru-bda-Isoq acts as a molecular water-oxidation catalyst. Remarkably, Ru-bda-Isoq@CTF-Bph achieves an excellent oxygen evolution rate of up to 2308 µmol g⁻¹ h⁻¹ under visible light irradiation for 5 h. The structural matching between the porous photosensitizer and molecular catalyst is found to play a very critical role in achieving the high performance, and the specificity and universality of this system are also highlighted. This strategy provides valuable insights into the design of efficient water oxidation photocatalytic systems.