Fe–N Bonded g‐C 3 N 4 /LaFeO 3 S‐Scheme Heterojunction Nanosheets as a Sunlight‐Driven Photocatalytic Antimicrobial Platform for Marine Antifouling

ABSTRACT Marine biofouling poses significant challenges to maritime industries and threatens environmental sustainability and ecological security. Photocatalytic antimicrobial platform has emerged as promising antifouling strategy in marine applications. In this study, an S‐scheme heterostructure of g‐C 3 N 4 /LaFeO 3 nanosheets with Fe─N bonding is constructed to serve as a highly efficient and stable photocatalytic antimicrobial platform for marine use. The material demonstrates excellent antifouling performance, achieving 99.9% eradication of E. coli and 100% degradation efficiency of methylene blue. Through combined experimental characterization and density functional theory calculations, a unique photochemical‐physical synergistic reinforcement mechanism is proposed. The S‐scheme heterojunction, featuring a built‐in electric field and Fe─N electron transfer channels, not only facilitates charge transfer and separation but also lowers the reaction energy barrier of key intermediates and accelerates surface photocatalytic kinetics, thereby promoting continuous reactive oxygen species generation. Furthermore, the nanosheet structures exhibit strong electrostatic attraction toward bacterial cell membranes, leading to physical insertion and membrane damage. This synergistic mechanism contributes to outstanding antibacterial and biofilm inhibition performance. Notably, the exceptional antifouling efficacy is maintained for approximately 180 d in real marine environments. These results underscore the practical potential and feasibility of the developed platform for real‐world applications in shallow sea settings.