Interfacial charge transfer and oxygen activation in phosphorus-doped g-C3N4/MoS2 quantum dot heterostructures: A first-principles and photocatalytic study

Abstract

A phosphorus-doped graphitic carbon nitride (PCN)/MoS2 quantum dots (QDs) heterostructure was synthesized via an evaporation-induced self-assembly process. X-ray photoelectron spectroscopy and work function analysis revealed strong interfacial electronic interactions. Density functional theory calculations indicated that interfacial charge migration was dominated by a diffusion-driven mechanism. Incorporation of MoS2 QDs modulated the electronic structure of PCN, significantly enhancing O2 adsorption and promoting the generation of reactive oxygen species (1O2 and ·O2–) under simulated solar irradiation. These electronic modifications improved the photocatalytic response, as demonstrated by the enhanced degradation of Rhodamine B and tetracycline (TC), with pollutant removal efficiencies of 99.5% and 90.0%, respectively, substantially exceeding those of pristine PCN. Application to real printing and dyeing wastewater demonstrated the material’s practical potential, with the degradation products of TC exhibiting substantially reduced biotoxicity to aquatic organisms. This study provides mechanistic insights into charge transport and interfacial oxygen activation in g-C3N4-based heterostructures, offering a rational strategy for the design of advanced photocatalysts for solar-driven environmental remediation.