Optimizing the band structure of sponge-like S-doped poly(heptazine imide) with quantum confinement effect towards boosting visible-light photocatalytic H2 generation

• Published in: Journal of colloid and interface science 2023-08, Vol.644, p.116-123
• Main Authors: Gao, Yang, Li, Yuxuan, Shangguan, Li, Mou, Zhigang, Zhang, Hui, Ge, Dachuan, Sun, Jianhua, Xia, Feifei, Lei, Weiwei
• Format: Article
• Language: English
• Subjects: Band structure; Carbon nitride; Photocatalytic hydrogen generation; Quantum confinement effect; S-doped
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2023.03.208

Sponge-like S-doped poly(heptazine imide) with optimized band structure (including up-shifted CB position and newly generated sub-band) has been successfully fabricated towards boosting visible-light photocatalytic H2 generation. [Display omitted] •A series of 3D hierarchical sponge-like S-doping PHIs (HS-SPHIs) are fabricated for the first time.•The visible-light response range of HS-SPHI is extended due to the generation of sub-band owing to the S doping.•The CB position is up-shifted due to the quantum confinement effect.•A remarkable AQY for photocatalytic H2evolution of 14.67 % at 420 nm is achieved. Simultaneously manipulating the nanostructure and band structure of semiconductors for boosting the photocatalytic performance of photocatalyts is highly desirable. Herein, a series of hierarchical sponge-like S-doped poly(heptazine imide) (HS-SPHI) assembled by ultrathin nanosheets were successfully fabricated via a facile bottom-up supramolecular preassembly approach using melamine (MA) and trithiocyanuric acid (TTCA) as precursors. Benefiting from the synergistic effect of the S-doping and their unique hierarchical porous structure coupled with quantum confinement effect, the as-obtained HS-SPHIs are endowed with extended visible-light response, improved charge separation efficiency, enlarged specific surface area, and enhanced thermodynamic driving force for water reduction. As a result, all the HS-SPHIs exhibit remarkable boosting visible-light (>420 nm) photocatalytic H2evolution (PHE). The maximum PHE rate achieved by HS-SPHI-650 can be up to 3584.2 μmol g−1h−1, with an apparent quantum efficiency (AQE) of 14.67 % at 420 nm, which is about 22.4 times than that of pristine bulk g-C3N4 (B-GCN). We believe that this work will provide a significant strategy for optimizing the band structure of PCN in order to improve its photocatalytic performance.