<p>Waterborne microbial contamination represents a significant global environmental challenge. Microorganisms can induce water pollution, precipitating infectious disease outbreaks and posing a substantial threat to human health. Currently, the excessive use of conventional antibiotics has resulted in the emergence of bacterial resistance, posing a challenge to the design and development of antimicrobial agents with high antibacterial efficacy in diverse water such as rivers, lakes, and wastewater from microbiology laboratories. Bimetallic nanomaterials, that amalgamate the distinctive characteristics of diverse metals, are garnering attention due to their synergistic properties. In this study, PVP-FeMo₂S₃ (PVP: Polyvinylpyrrolidone) and PVP-ZnMo₂S₃ nanocrystals were synthesized by a high-temperature reaction. The prepared nanocrystals exhibited excellent biocompatibility, regular morphology, long-term stability, and remarkable antibacterial effects. The bacterial biofilms could be eradicated by the combination of photothermal (PTT) and photodynamic synergistic effects of PVP-FeMo₂S₃ and PVP-ZnMo₂S₃ nanocrystals. PVP-ZnMo₂S₃ nanocrystals exhibited enhanced PTT conversion efficiency for water treatment. Remarkably, even after 20 cycles of recycling, PVP-ZnMo₂S₃ retained substantial antibacterial efficacy. The excellent biosafety of PVP-ZnMo₂S₃ further guarantees the safety of water quality post-treatment. Thus, PVP-ZnMo₂S₃ bimetallic nanocrystals can serve as a novel antimicrobial agent for the treatment of microbial contamination in water. This study offers a potential strategy to mitigate secondary water pollution and prevent the development of drug resistance among pathogenic microorganisms.</p>