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

摘要

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 SiO 2 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 delocalizedπ-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•O 2-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.