A conjugated polymer coupled with graphitic carbon nitride for boosting photocatalytic hydrogen generation under visible light

In this work, a soluble C-6-alkyl chain functionalized fluorene-dibenzothiophene-S,S-dioxide (C-6-FDTP) conjugated polymer was synthesized and further used to fabricate a C-6-FDTP/g-C3N4 hybrid through a facile solvent-evaporation process. The polymeric heterojunction in the hybrid is composed of the FDTP backbone and tri-s-triazine of carbon nitride via pi-pi stacking. The performance of photocatalytic H-2 generation under visible light over C-6-FDTP/g-C3N4 displays 15-fold higher H-2 generation rate with respect to bare g-C3N4. The H-2 generation rate even achieved 495 mu mol h(-1) g(-1) when Pt was used as a cocatalyst, which presented overwhelming advantages over pristine g-C3N4 under visible light irradiation. The enhancement mechanism was investigated by means of a series of characterization studies. Enhanced light harvesting promoted charge separation and charge transfer was identified, accounting for the superior photocatalytic activity. A type II heterostructure mechanism is assigned for the role of the C-6-FDTP conjugated polymer, and the polymeric pi-pi stacked heterojunction provided channels for charge separation and transfer. This work provides a research basis for the fabrication of efficient conjugated polymer photocatalysts with promising applications in industrial photocatalytic H-2 generation.