Sulfur-doped g-C3N4/g-C3N4 isotype step-scheme heterojunction for photocatalytic H2 evolution

The rational fabrication of an efficient heterojunction is critical to the enhancement of photocatalytic hydrogen (H2) evolution performance. Herein, a new-fashioned graphitic-carbon nitride (g-C3N4) based isotype step-scheme (S-scheme) heterojunction composed of sulfur-doped and sulfur-free active sites is developed by liquid sulfur-mediation of exfoliated g-C3N4. Particularly, the liquid sulfur not only contributes to the full contact between sulfur species and exfoliated g-C3N4, but also creates sulfur-doping and abundant pores, since self-gas foaming effect of sulfur vapor. Moreover, the S-doped and S-free active sites located in the structural unit of C3N4 jointly construct a typical sulfur-doped g-C3N4/g-C3N4 isotype step-scheme heterojunction, which endows highly efficient photocatalytic reaction process. Therefore, the optimal sample possesses remarkable photocatalytic H2 evolution activity (5548.1 μmol g−1 h−1) and robust durability. Most importantly, the investigation will open up a new path for the exploration of other carbon-based isotype S-scheme heterojunctions.