Self-assembly synthesis of phosphorus-doped tubular g-C3N4/Ti3C2 MXene Schottky junction for boosting photocatalytic hydrogen evolution
Kelei Huang, Chunhu Li, Xiuli Zhang, Liang Wang, Wentai Wang, Xiangchao Meng
Abstract
Establishing highly effective charge transfer channels in carbon nitride (g-C 3 N 4 ) to enhance its photocatalytic activity is still a challenging issue. Herein, the delaminated 2D Ti 3 C 2 MXene nanosheets were employed to decorate the P-doped tubular g-C 3 N 4 (PTCN) for engineering 1D/2D Schottky heterojunction (PTCN/TC) through electrostatic self-assembly. The optimized PTCN/TC exhibited the highest hydrogen evolution rate (565 μmol h −1 g −1 ), which was 4.3 and 2.0 -fold higher than pristine bulk g-C 3 N 4 and PTCN, respectively. Such enhancement may be primarily attributed to the phosphorus heteroatom doped and unique structure of 1D/2D g-C 3 N 4 /Ti 3 C 2 Schottky heterojunction , enhancing the light-harvesting and charges’ separation. One-dimensional pathway of g-C 3 N 4 tube and built-in electric field of interfacial Schottky effect can significantly facilitate the spatial separation of photogenerated charge carriers, and simultaneously inhibit their recombination via Schottky barrier . In this composite, metallic Ti 3 C 2 was served as electrons sink and photons collector. Moreover, ultrathin Ti 3 C 2 flake with exposed terminal metal sites as a co-catalyst exhibited higher photocatalytic reactivity in H 2 evolution compared to carbon materials (such as reduced graphene oxide). This work not only proposed the mechanism of tubular g-C 3 N 4 /Ti 3 C 2 Schottky junction in photocatalysis , but also provided a feasible way to load ultrathin Ti 3 C 2 as a co-catalyst for designing highly efficient photocatalysts .