Enhanced Light-Driven Hydrogen-Production Activity Induced by Accelerated Interfacial Charge Transfer in Donor-Acceptor Conjugated Polymers/TiO2 Hybrid.

Donor-acceptor (D-A) conjugated polymers have proved to be desired candidates to couple with inorganic semiconductors for enhanced photocatalytic activity. Herein, the matched energy levels between polymer BFB and TiO2 make them form BFB-TiO2 composites with moderate photocatalytic H2 evolution rate (HER). To further enhance the interfacial interaction, BFB was modified with a carboxylic acid end group, which reacted with surface OH of TiO2 to form an ester bond. As a result, the functionalized BFBA-TiO2 composites exhibited superior photocatalytic activity. Especially, HER of 4 % BFBA-TiO2 can reach up to 228.2 µmol h-1 under visible light irradiation (λ>420 nm), which is about 2.02 times higher than that of BFB-TiO2 . The enhanced photocatalytic activity originated from the formed ester bond between polymer and TiO2 , and photogenerated electrons injection from lowest unoccupied molecular orbital (LUMO) of the exited polymer to conduction band of TiO2 were accelerated. Therefore, based on an intermolecular interaction mechanism, more suitable D-A conjugated polymers with anchoring groups could be designed to couple with other semiconductors for enhancing photocatalytic activity.