Cross‐Shaped Donor‐π‐Acceptor Covalent Organic Frameworks with Tunable Push–Pull Architectures for Effective Photocatalytic H ₂ O ₂ Production

Abstract

Abstract Efficient photocatalysts for H 2 O 2 production are pivotal for solar‐to‐chemical energy conversion. However, their performance remains limited by inefficient charge separation and rapid electron–hole recombination. Rational molecular design is therefore essential to enhance intrinsic charge‐separation driving forces and establish efficient transport pathways. Herein, a TCNQ‐based covalent organic framework (TCNQ‐COF) featuring a rare cross‐shaped donor‐π‐acceptor fragment was constructed by integrating electron‐deficient TCNQ and electron‐rich triphenylene into a conjugated backbone, achieving multidirectional charge‐transfer pathways. Post‐synthetic transformation of the cyano groups into electron‐withdrawing heterocycles (pyrazole or pyrimidine, Aʹ), when combined with triphenylene (D) and amino groups (D 1 ), yielded two novel COFs (Pz‐COF, Pym‐COF) with multilevel cross‐shaped D‐π‐Aʹ‐D 1 architectures. This sophisticated push–pull system enables gradient‐tuning of donor–acceptor interactions, thereby promoting efficient charge separation and carrier mobility. Among them, Pz‐COF exhibits the highest H 2 O 2 production rate (7613 µmol g −1 h −1 ). Spectroscopic and theoretical analyses further reveal a synergistic effect between acceptor strength and donor diversity in regulating intramolecular charge behavior. The proposed cross‐shaped D‐π‐A and its multilevel D‐π‐A′‐D 1 architectures overcome the limitations of conventional linear motifs, offering a blueprint for the development of advanced photocatalytic COFs.