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 μmol/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.