Facilitating carrier kinetics in ultrathin porous carbon nitride through shear-repair strategy for peroxymonosulfate-assisted water purification

Abstract

Achieving high specific surface area (HSSA) in graphitic carbon nitride (g-C3N4) severely depolymerizes the molecular chain structure, resulting in sluggish carrier kinetic behaviors and thus moderated water purification performance in photocatalytic peroxymonosulfate (PMS) activation system. Herein, we report a versatile shear-repair strategy for fabricating ultrathin porous g-C3N4 nanosheets with a thickness of 1.5 nm, HSSA (138.5 m2 g−1), and highly polymerized molecular chains. This strategy accelerates exciton dissociation and charge carrier separation, with the exciton binding energy decreasing from 65.7 to 47.5 meV. Crucially, the electron-donating pollutant and electron-withdrawing PMS generate a microelectric field at the g-C3N4 surface that activates PMS to generate 1O2 sustainably. Consequently, our catalyst exhibits an exceptional imidacloprid (IMD) removal performance with a rate constant of 0.405 min−1 and remarkable PMS utilization efficiency (90% within 15 min). Moreover, under real conditions of sunlight irradiation, we observe an outstanding pollutants’ removal efficiency with a near-100% degradation rate over 20 days of continuous operation. Our work emphasizes the feasibility of synergistic molecular-level structural engineering for refining carrier kinetic behaviors in high-performance photocatalyst design.