Construction of g-C3N4/CdS-Cu Z-scheme heterojunction with reactive oxygen species compensation function and analysis of its photocatalytic antibacterial mechanism

Abstract

Photocatalytic antibacterial materials, which kill bacteria by generating reactive oxygen species (ROS) without relying on metal ion components, offer higher safety and environmental friendliness, making them a key focus of current antibacterial research. Traditional photocatalytic materials exhibit limited responsiveness to visible light, and their antibacterial efficacy diminishes when the generation of ROS is suppressed. Therefore, this study developed a g-C₃N₄/CdS-Cu Z-scheme heterojunction with strong visible light responsiveness, enabling the generation of alternative ROS when one type is inhibited. The material exhibited excellent antibacterial performance under visible light, with antimicrobial rates of 95.46 % and 95.91 % against E. coli and S. aureus, respectively. Microstructural and photoelectric analyses confirmed that the material possessed a tightly coupled two-dimensional heterostructure with full-spectrum absorption capacity and efficient separation of photogenerated charge carriers. Additionally, density functional theory (DFT) calculations revealed changes in electron transfer pathways and energy band structure, further supporting the proposed antibacterial mechanism. In practical application tests, g-C₃N₄/CdS-Cu showed good performance in water treatment. This study on the “ROS compensation” mechanism provides a theoretical basis for the development of advanced photocatalytic antibacterial materials and expands their application range.