Surfactant-Assisted Microbial Mineralized Synthesis of Antimony Sulfide Nanoparticles for Visible Light Catalytic Disinfection: Performance and Mechanism

Efficient and sustainable visible-light (VL) photocatalysts for bacterial inactivation are crucial for advanced water disinfection and safe water supply. A surfactant-assisted microbial mineralization approach was developed to construct highly crystalline and defect-engineered antimony sulfide nanoparticles (Sb2S3 NPs). Sodium dodecyl sulfate (SDS) served as a surfactant that effectively regulated sulfur-vacancy (Vs) concentration and crystal structure, thereby enhancing photoinduced charge separation and suppressing carrier recombination. The optimized Sb2S3 NPs (SM-Sb) possessed an ordered orthorhombic structure, uniformly small particle size (∼146 nm), and abundant Vs defects, enabling broad light absorption (241–716 nm) with strong absorption in the visible region above 420 nm. When employed as the photocatalyst, SM-Sb achieved over 99% inactivation of Escherichia coli K12 and Bacillus subtilis under VL irradiation. Radical trapping and electron paramagnetic resonance (EPR) analysis revealed that photogenerated holes (h+) and superoxide radicals (•O2–) dominated the bactericidal process, while Vs-induced internal electric fields facilitated hierarchical reactive oxygen species (ROS) release, including •O2–, hydroxyl radicals (•OH), and hydrogen peroxide (H2O2). Furthermore, the negatively charged surface of SM-Sb reduced nonspecific bacterial adsorption, minimizing catalyst loss ensuring stable performance and high recyclability during multiple disinfection cycles. Overall, this work establishes a defect- and interface-engineering strategy for VL-responsive Sb2S3 NPs, providing mechanistic insights into the interplay between vacancy defects, charge-transfer dynamics, and interfacial ROS-mediated antibacterial activity, and highlighting the potential of SM-Sb in advanced antimicrobial nanomaterial applications.