Work

Boosting n→π∗ electronic transition via reducing interlayer stacking distance in red Poly(heptazine imide) towards efficient photocatalytic H2 production

Year: 2026

Type: article

Abstract: Poly(heptazine imide) (PHI) exhibits exceptional photocatalytic performance due to its unique structural advantages. However, its effectiveness is limited by a narrow light response range and inefficiencies in charge carrier separation and transfer. Herein, we introduce an innovative approach to synthesize red PHI (RPHIx) with a reduced interlayer distance and a highly in-plane ordered structure by calcining melon-based carbon nitride with KSCN at varying target calcination temperature. The compact interlayer π-π stacking facilitates n→π∗ electronic transition, thereby broadening the range of light absorption and enhancing the separation of photo-induced carriers. The resulting RPHI600 reveals a remarkable photocatalytic H 2 evolution reaction (HER) rate that is 85 times higher than that of pristine PHI under 510< λ < 780 nm irradiation. Moreover, the improved in-plane integrity and reduced interlayer distance facilitate the transfer of charge carriers in both horizontal and vertical directions, leading to an HER rate 2.3 times greater than that of PHI under 420< λ < 780 nm illumination. This work offers valuable insights for enhancing the light-harvesting capability and crystallinity of PHI-based photocatalyst.

Source: International Journal of Hydrogen Energy

DOI: 10.1016/j.ijhydene.2026.153828