Side-chain regulated topology of 2D covalent organic frameworks and its impact on photocatalytic synthesis of H2O2

Abstract

The development of covalent organic frameworks (COFs) with efficient photocatalytic H₂O₂ generation and building the structure–performance relationships are essential to rationally design and construct COFs for photocatalysis. Herein, COFs with kgm and fes underlying nets were successfully prepared via tuning the side-chain length of organic building units to investigate topological effects on H₂O₂ photosynthesis. We found that an ethoxy group-based fes COF, HIAM-0023 (HIAM = Hoffmann Institute of Advanced Materials), exhibits a much higher H₂O₂ generation rate (149.5 μmol g⁻¹ h⁻¹) than a non-substituted kgm type COF (68.9 μmol g⁻¹ h⁻¹). Furthermore, an enhanced photocatalytic efficiency of 391.7 μmol g⁻¹ h⁻¹ is obtained using mixed-linker HIAM-0023 with 37.5% hydroxyl substitution. This work sheds light on the rational construction of COFs with controllable topologies and compositions to realize efficient H₂O₂ photosynthesis.