Photoelectron Migration Monitored by Charge Transfer Channels in Covalent Organic Frameworks for Boosting Photocatalytic Hydrogen Evolution

ABSTRACT

Covalent organic frameworks (COFs) are promising organic semiconductors in solar‐driven green hydrogen production. Promoting separation and migration of charge carriers is pivotal to achieve high hydrogen evolution efficiency. Herein, a structural and electronic engineering strategy has been presented through integrating the ketoenamine‐linked COFs containing ‐CF ₃ groups (TpPa‐ x CF ₃ , x = 0, 0.5, and 1) with cupric oxide (CuO) to form CuO@TpPa‐ x CF ₃ dyad. The ‐CF ₃ introduction enhances the amount of charge transfer channels between donor and acceptor units in TpPa‐xCF ₃ , thereby promoting electron‐hole separation and photogenerated electron migration from TpPa‐xCF ₃ to CuO, resulting in improved photocatalytic hydrogen production kinetics. The hydrogen evolution rate of CuO/TpPa‐CF ₃ reaches 7354 µmol g ⁻¹ h ⁻¹ , which significantly surpasses those of CuO/TpPa‐0.5CF ₃ (3789 µmol g ⁻¹ h ⁻¹ ) and CuO/TpPa (1823 µmol g ⁻¹ h ⁻¹ ), and even Pt‐based counterpart (6115 µmol g ⁻¹ h ⁻¹ ). This work provides a new strategy to construct noble‐metal‐free COF‐based photocatalytic systems for hydrogen production.