Preparation of enhanced AgI@MnO2 heterojunction photocatalysts for rapid sterilization under visible light

Highlights: : • AgI@MnO₂ has higher use efficiency of visible light than AgI and MnO₂. • AgI@MnO₂ has higher separation efficiency of photo-induced electron-hole pairs. • The mechanism for the enhanced photocatalytic activity of AgI@MnO₂ is revealed. • AgI@MnO₂ has a superior photocatalytic activity for the sterilization of E. coli and S. aureus. -- Abstract: Aimed at solving food poisoning and food-borne diseases caused by drug-resistant pathogens bacteria, the optimum utilization of abundant, green, and sustainable sunlight through photocatalytic technology is definitely an appealing task. Herein, a new series of AgI@MnO₂^X:1 (X = 5, 10, 15) heterostructure photocatalysts were synthesized by in-situ growth of AgI nanoparticles on the surface of MnO₂ microspheres using the deposition method. Compared with MnO₂ or AgI alone, the AgI@MnO₂ heterostructure system exhibited enhanced photocatalytic performance due to the improved rapid separation efficiency of photogenerated electron-hole pairs. Moreover, AgI@MnO₂^10:1 had higher photocurrent density and more ROS production, indicating the accelerated charge transfer and increased photocatalytic efficiency. Based on this, the photocatalytic mechanism was proposed. The antibacterial experiment verified the excellent broad-spectrum bactericidal performance of AgI@MnO₂^10:1 against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), which was because AgI@MnO₂^10:1 with high catalytic activity under visible light would generate more ROS by consuming glutathione (GSH) to improve antibacterial efficiency. This study provides new insight into the development of superior general photocatalyst for environmental disinfection, healing wounds from bacterial infections, and other fields that quickly kill bacteria.