Constructing S-scheme PDPB/Ag-TiO₂ heterojunctions with a powerful internal electric field for facilitating photocatalytic hydrogen evolution

S-scheme heterojunction catalysts have attracted much attention due to their ability to effectively separate photo-generated electrons and holes while optimizing the redox ability of carriers. We have prepared an efficient visible-light catalytic PDPB/Ag-TiO2 S-scheme heterojunction by in-situ synthesis methods. The catalysts were characterized for their structure, composition, morphology, and photoelectrochemical properties. The hydrogen production rate of PDPB/Ag-TiO2-2 was 1473.6 mu mol/g/h. The results of SPV analysis showed that the spontaneous interfacial charge transfer from PDPB to Ag-TiO2 in the contact interface region resulted in the presence of an internal electric field. This enhanced internal electric field effectively drove directional charge migration through the S-scheme mechanism, improving charge separation and utilization. The PDPB/Ag-TiO2-2 composites also maintained stable photocatalytic activity after running for four cycles. Overall, this study brings fresh preparation ideas for the conjugated polymer-TiO2 composites with high photocatalytic efficiency.