Thiophene-containing conjugated polymers modified Zn0.5Cd0.5S inorganic/organic S-scheme heterojunction for boosting photocatalytic hydrogen production coupled with benzyl alcohol oxidation

To achieve efficient artificial photosynthesis of hydrogen production coupled with benzyl alcohol oxidation, it is imperative to address the key kinetic bottlenecks that limit photocatalysis performance comprehensively. Herein, we synthesized a D-A conjugated polymer pyrene-thienothiophene (PyTT) containing thiophene rings acceptor unit via a direct C-H arylation reaction. Subsequently, an innovative ZCS/PyTT inorganic/organic S-scheme heterojunction was successfully constructed by synthesizing Zn0.5Cd0.5S (ZCS) nanocrystals in situ on the surface of PyTT nanosheets. By enabling this design, the optimized ZCS/5PyTT heterojunction exhibits significantly enhanced rates of H2 and benzaldehyde (BAD) production at 4.52 and 4.12mmol g- 1h- 1 respectively under only two sun light intensity, which are 2.69 and 2.80 times higher than pristine ZCS. The outstanding photocatalytic performance can be attributed to the efficient charge separation and transfer efficiency, enhanced light absorption capability, as well as increased concentration of active carriers in reaction. Particularly, the interface charge transfer mechanism involved in ZCS/PyTT S-scheme heterojunction is comprehensively investigated through in situ irradiated X-ray photoelectron spectroscopy (XPS) and photo-irradiated Kelvin probe force microscopy (KPFM) analyses. This study provides a protocol for preparing specific inorganic/organic S-scheme heterojunction photocatalysts aimed at achieving efficient cooperative photo-redox coupling of H2 production and organic transformations.