Reinforced ROS Generation and Anti-Photocorrosion for Boosted Photooxidation Disinfection by IEF-Enhanced Type II Charge Carrier Dynamics

Abstract

The internal electric field (IEF) is key in speeding up the separation and transfer of photogenerated carriers, which boosts the production of reactive oxygen species (ROS). In this study, we present a novel silver iodide/N-rich carbon nitride (AgI/C₃N₅) heterojunction catalyst with an IEF directed from AgI to C₃N₅. We confirmed this IEF using density functional theory (DFT) calculations and various characterization methods. This IEF induces and reinforces the Type II transfer pathway for carrier separation and transfer, significantly increasing the production of ROS, particularly singlet oxygen (¹O₂). As a result, the AgI/C₃N₅ catalysts achieve 10.1 times the disinfection efficiency of C₃N₅ and 5.6 times that of AgI, under one-min reaction time, 10⁷ CFU/mL of E. coli, visible light, and room temperature. It also outperforms most other AgI and carbon nitride-based heterojunction photocatalysts. Notably, the photogenerated holes (h⁺) selectively oxidize superoxide radicals (∙O₂⁻) to ¹O₂ due to favorable energy alignment, minimizing O₂ reduction effects and enhancing photocorrosion resistance, as demonstrated in five consecutive cycling experiments. In addition, the actual water disinfection tests confirmed its practical application potential. This work highlights the AgI/C₃N₅ heterojunction catalyst's promise as an efficient disinfection agent and sheds light on the photocatalytic disinfection mechanism.

Keywords

enhanced photocorrosion resistance / internal electric field / reinforced ROS generation / type II charge transfer pathway / water disinfection

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