The enhanced charge separation over dual Z-scheme MoS2@g-C3N4/ZIF-8(Zn) photocatalyst: The boosted Fenton activation model and DFT calculation

Abstract

The synergistic effects of photocatalytic activation Fenton reaction is considered to be a promising method to degrade the organic contaminant. Herein, a dual Z-scheme MoS2@g-C3N4/ZIF-8(Zn) (donated as MCZ) heterojunction is designed via a simple assembly approach. The ultraviolet photoelectron spectroscopy (UPS), Mott-Schottky curves (M-S), transient photovoltage (TPV), X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculation reveal the electron transfer from n-type g-C3N4 or ZIF-8(Zn) to p-type MoS2, providing the platform for band construction and dual Z-scheme model. The optional modulation of the MCZ-x conjunction has efficiently separated photogenerated charge and significantly reactive species through Fenton activation under visible light irradiation. The results indicate that the degradation efficiency of methylene blue (MB) and oxytetracycline (OTC) by MCZ-7.5 could reach 99.7% and 97% only within 30 s and 5 min, respectively, much higher than that of MCZ + vis and MCZ + Fenton. Electron-spin-resonance (ESR) and radical scavenger experiments confirm that the ·OH and ·O2– are the dominated reactive oxygen species (ROS). It is speculated the MoS2 based double Z-pathway heterostructure can accelerate coupling effect of photocatalytic and Fenton reaction in solving practical environmental issues.