Few-layer graphitic carbon nitride for enhanced visible-light photocatalytic efficiency: the role of narrow bandgap and nitrogen-vacancies. Issue 12 (27th October 2022)

• Record Type: Journal Article
• Authors: Huang, Qiang; Liu, Yang; Bai, Wenhui; Hong, Jiahui; Ai, Yuejie; Chen, Zhe
• Is Part Of: Environmental science. Volume 9:Issue 12(2022)
• Page Start: 4445
• Page End: 4458
• Publication Date: 2022-10-27
• Subjects: Environmental sciences -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d2en00785a
• Languages: English
• ISSNs: 2051-8153

Abstract

Abstract : A 1.4 nm graphitic carbon nitride photocatalyst was fabricated for organic contaminant degradation and the photocatalytic mechanism with nitrogen vacancies and few-layer structure was revealed. Abstract : Graphitic carbon nitride (g-C3 N4 ) is a famous photocatalyst with vast prospects in the field of visible-light photocatalysis, however, its actual performance has been inhibited by its feeble efficiencies in charge-carrier separation and transfer. Construction of two-dimensional g-C3 N4 is one of the widely used strategies to improve its photocatalytic activity. Here, we proposed a facile spatial confinement synthesis method to synthesize a few-layer g-C3 N4 nanosheet with significantly enhanced photocatalytic activity. With the aid of spatial confinement synthesis, the few-layer structure (∼1.4 nm) and introduction of nitrogen vacancies (NVs) were simultaneously achieved. The obtained few-layer g-C3 N4 nanosheet showed a significantly higher (23.25-fold) BPA degradation rate of 3.162 h −1 than that of the bulk g-C3 N4 (B-C3 N4 ) under visible light irradiation. Meanwhile, the few-layer g-C3 N4 nanosheet had good recyclability and excellent degradation performances toward different types of organic contaminants (phenolic compounds, antibiotics, etc. ) under visible light irradiation. Many typical phenolic compounds were degraded by more than 40% in 3 h, and the antibiotic tetracycline was 100% oxidized in 60 min. Further characterization showed that the enhanced photocatalytic activity was assigned to the increased active sites, stronger photo-adsorption ability, and narrower bandgap of 2.32 eV. The density functional theory (DFT) calculations demonstrated that the introduction of NVs and the g-C3 N4 structure changing from bulk to few layers were associated with the lowering of bandgap energy, increased active sites, and stronger photo-adsorption ability. It is expected that this work could provide a new perspective on the fabrication of highly efficient g-C3 N4 -based photocatalysts.