Appropriate oxygen vacancies and Mo-N bond synergistically modulate charge transfer dynamics of MoO3_x/S-CN for superior photocatalytic disinfection: Unveiling synergistic effects and disinfection mechanism

Highly efficient charge transfer is a critical factor to modulate the photocatalytic activity. However, the conscious modulation of charge transfer efficiency is still a great challenge. Herein, a novel interfacial Mo-N bond and appropriate oxygen vacancies (OVs) modulated S-scheme MoO3_x/S-CN heterojunction was rationally fabricated for efficient photocatalytic disinfection. The results of characterizations and density functional theory (DFT) calculations suggested that the enhanced charge transfer dynamics is ascribed to the optimizing oxygen vacancies density and forming interfacial Mo-N bond. It can improve charge transfer efficiency from 36.4% (MoO3_x) to 52.5% (MoO3_x/S-CN) and produce more reactive oxygen species (ROS), achieving entirely inac-tivate of 7.60-log E. coli and S. aureus within 50 min and 75 min. Besides, MoO3_x/S-CN can well resist the disturbance from the coexisting substances, and can be applied in a wide pH range, and even authentic water bodies. Monitoring of bacterial antioxidant systems and membrane integrity revealed that bacterial inactivation begins with the oxidation of cell membrane and dies from leakage of intracellular substances and destruction of cell structure. This work provides an inspiration on consciously modulating S-scheme charge transfer efficiency by optimizing oxygen vacancies density and atomic-level interface control for promoting the photocatalytic antibacterial activity.

Automated summary

A novel MoO3_x/S-CN heterojunction with an interfacial Mo-N bond and appropriate oxygen vacancies was fabricated to achieve efficient photocatalytic disinfection. The enhanced charge transfer dynamics, achieved through optimizing oxygen vacancies density and forming interfacial Mo-N bond, improved charge transfer efficiency from 36.4% to 52.5% and increased the production of reactive oxygen species. The MoO3_x/S-CN heterojunction successfully inactivated E. coli and S. aureus within 50 minutes and 75 minutes, respectively, and demonstrated resistance to coexisting substances and applicability in a wide pH range and real water bodies.