Construction of Modifiable Phthalocyanine-Based Covalent Organic Frameworks with Irreversible Linking for Efficient Photocatalytic CO₂ Reduction

Phthalocyanine-based covalent organic frameworks photocatalysts (CoOP, CoPOP, and CoBOP) with irreversible covalent linking were synthesized by designing bis-phthalonitrile precursors, exhibiting exceptional stability in thermal, acidic, alkaline, and organic environments. Tuning the conjugation length of the linking unit effectively modulates the electronic features of the photocatalyst. The linking unit serves as a ‘ladder’ between excited [Ru(bpy)₃]Cl₂ and Co²⁺, allowing the electrons to cascade down and facilitating rapid transfer, which is responsible for the excellent photocatalytic CO₂ reduction reaction performance of the photocatalysts.