Molecular Design of Covalent Triazine Frameworks with Anisotropic Charge Migration for Photocatalytic Hydrogen Production

Covalent triazine frameworks (CTFs) represent promising polymeric photocatalysts for photocatalytic hydrogen production with visible light. However, the separation and transfer of charges in CTFs are isotropic because of the uniform distribution of donor-acceptor motifs in the skeleton. Herein, to achieve the anisotropic charge carrier separation and migration, thiophene (Th) or benzothiadiazole (BT) unit is selected as the dopant to modify the molecular structure of CTF-based photocatalysts. Both theoretical and experimental studies reveal that the incorporation of Th or BT units induces the anisotropic charge carrier separation and migration at the interface of CTFs. The optimized polymer manifests a much enhanced photocatalytic activity for photocatalytic hydrogen production with visible light, and thus this study provides a useful tool to design conjugated polymer photocatalysts at the molecular level for solar energy conversion.

Automated summary

Covalent triazine frameworks (CTFs) have the potential to be efficient photocatalysts for hydrogen production using visible light. However, the uniform distribution of donor-acceptor motifs in the CTFs leads to isotropic charge separation and transfer. In this study, thiophene (Th) or benzothiadiazole (BT) units were incorporated into the molecular structure of CTF-based photocatalysts to achieve anisotropic charge carrier separation and migration. The optimized polymer exhibited significantly enhanced photocatalytic activity for hydrogen production under visible light, providing a useful approach for designing conjugated polymer photocatalysts for solar energy conversion.