Boosting pollutant degradation with simultaneous H2O2 production from its electron delocalization and excitation co-triggered by microelectric field and visible light

Abstract

Novel electron delocalization and excitation of pollutants triggered by a microelectric field (MEF) on the g-C₃N₄ surface and visible light was, for the first time, introduced in a dual-photocatalytic system, which greatly boost the pollutant degradation with simultaneous H₂O₂ production of dual photocatalysis. MEF was established on the surface of g-C₃N₄ by simply replacing its connecting N-sites (N–C₃) with a benzene ring, transferring electrons of the benzene ring to the heptazine of g-C₃N₄ and storing them to establish an electron impurity level (EIL), which was excited by visible light to reduce O₂ to H₂O₂. Then, MEF further transferred electrons of bisphenol A (BPA) and phenolic intermediates spontaneously absorbed on the benzene ring to fill up the electron deficiency of the EIL to maintain its continuous excitation, which strengthened the light absorption of g-C₃N₄ without generating holes and enriched the electron number for H₂O₂ production. Meanwhile, BPA and its degraded phenolic intermediates underwent self-cracking and intrinsic photocatalytic degradation on the HOMO of RSN (g-C₃N₄ modified with MEF), which prevented them from capturing electrons on reduction sites. Consequently, RSN10 with an optimal MEF showed a remarkable BPA degradation percentage of 100% with simultaneous H₂O₂ production of 65.82 μmol L⁻¹ under 40 min visible light irradiation. This work provides a new strategy for directing the conversion of pollutant energy to chemical energy and breaking the intrinsic photocatalysis contradiction, which has great sustainability implications for pollutant treatment and recovery.