Regulating the photoexcited carrier transfer efficiency over graphdiyne/ Ag3PO4 S-Scheme heterojunction for photocatalytic hydrogen production

The heterogeneous structure formed after the contact of catalysts can change the transport path of the internal carriers and thus regulate the photocatalytic activity. GDY (graphdiyne) has good conductivity, in this paper, GDY/Ag3PO4 was synthesised by electrostatic self-assembly. According to the photocatalytic hydrogen evolution test, the hydrogen evolution capacity reached 5100 mu mol center dot g- 1 center dot h- 1, which significantly improved the photocatalytic hydrogen evolution ability compared with GDY (283 mu mol center dot g-1 center dot h-1) and Ag3PO4 (552 mu mol center dot g- 1 center dot h- 1). In addition, a variety of characterization methods (fluorescence analysis, electrochemical testing and in situ XPS, etc.) and DFT calculation were used to prove the successful preparation of GDY/Ag3PO4 and probe into the underlying cause for the enhancement of its photocatalytic hydrogen-producing performance. From the lightexcited carrier displacement and the location of conduction and valence bands of the catalyst, it can be speculated that the catalysts GDY and Ag3PO4 contact with each other to form S-type heterojunction. The presence of Ag3PO4 enhances the light utilization ratio of the catalyst GDY/Ag3PO4, and the presence of GDY offers plentiful hydrogen evolution active sites for GDY/Ag3PO4. The photocatalytic hydrogen evolution rate of GDY/Ag3PO4 is greatly enhanced by the improvement of visible light absorption intensity and the increase of photogenerated carrier migration efficiency. To sum up, it has a certain development prospect to realize high-activity photocatalytic hydrogen evolution by constructing catalyst heterostructures with "high-speed electronic channels".