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

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 nanoparti-cles. The resulting material showed great optical and textural characteristics with plenty of open and uni-form pores, which are very helpful whether for multiple light scattering or mass transfer. The formation of boosted delocalized pi-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 center dot 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 energeti-cally 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.(c) 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.