A unique and well-designed 2D graphitic carbon nitride with sponge-like architecture for enhanced visible-light photocatalytic activity

Abstract

A unique and well-designed 2D graphitic carbon nitride (g-CN) with sponge-like architecture has been successfully synthesized by engineering supramolecular self-assembly and well-organized SiO2 nanoparticles. The resulting material showed great optical and textural characteristics with plenty of open and uniform pores, which are very helpful whether for multiple light scattering or mass transfer. The formation of boosted delocalized π-conjugated electrons at the molecular level and condensed heptazine building blocks result in enhanced carrier density and charge transfer dynamics. Optical emission spectroscopy and time‐resolved fluorescence lifetime (TRPL) strongly confirmed the enhancement of light harvesting and prolonged charge carrier lifetime. The optimized sample exhibited a degradation performance of 95% of bisphenol A (BPA, 10 mg L–1) after 60 min under visible–light irradiation at pH = 5. All the scavenging experiments, probing experiments as well as electron paramagnetic resonance (EPR) confirm that •O2– is the dominant reactive species that fragments bisphenol A. Interestingly, density functional theory (DFT) calculations unveil that the BPA interaction with a modified g-CN containing porous structure is energetically more favorable than non-porous pure g-CN. Moreover, the toxicity assessment showed that the final degradation products were placed in the non-harmful category based on acute and chronic toxicity. This study presents a promising strategy to modify the g-CN properties and provides an efficient technique for boosting its visible–light photocatalytic activity.