Thin-wall hollow porous cystic-like graphitic carbon nitride with awakened n→π* electronic transitions and exceptional structural features for superior photocatalytic degradation of sulfamethoxazole

Abstract

Effective photoexcitation and carrier migration are the essential aspects to strengthen semiconductor-engaged redox reaction. Herein, a three-dimensional thin-wall hollow porous cystic-like g-C₃N₄ (HPCN) with curved layer edge was successfully fabricated via a non-template thermal-condensation strategy. The construction of unique distorted structure can evoke the hard-to-activate n→π* electronic transition to some extent, broadening the absorption spectrum to 800 nm. And benefiting from the multiple reflections of incident light, the effective photoactivation can be further achieved. Moreover, the thin-wall porous framework can shorten the diffusion distance and accelerate migration of photogenerated charge, favouring interfacial redox reactions. The optimized HPCN_1.0 demonstrated an excellent photocatalytic degradation of SMX under blue-LED light irradiation, which was dramatically superior to that of pristine g-C₃N₄ (CN, 11.4 times). Ultimately, in consideration of reactions under several influencing factors with four different water samples, we demonstrated that the HPCN photocatalyst could be utilized far more productively for the elimination of SMX under real-world aqueous conditions. This work provides a straightforward approach for the removal of SMX and has immense potential to contribute to global scale environmental remediation.

Keywords: Mechanism; Photocatalysis; Sulfamethoxazole; Three-dimensional distorted g-C(3)N(4); n→π* electronic transition.