In Situ Real‐Time and Reusable Antibacterial Mask Based on CoO@Ag Nanozyme with Enhanced Catalytic Activity

Abstract Daily mask‐wearing is a critical strategy for preventing pathogen infections and curbing their rapid spread. However, the widespread use of disposable commercial masks not only escalates microplastic pollution but also acts as a mobile carrier for pathogenic bacteria, further fueling their dissemination. To address these challenges, a facile room‐temperature reduction method is employed to synthesize CoO@Ag nanozyme with enhanced catalytic activity. The Ag‐decorated CoO nanozyme exhibits robust catalytic enzyme‐like activity, rapidly generating abundant surface‐bound singlet oxygen ( ¹ O ₂ ) and hydroxyl radicals (·OH) to effectively inactivate bacteria. The prepared CoO@Ag‐PAN (CAP) mask exhibits exceptional in situ real‐time antibacterial properties, enabling bacterial inactivation within 20 min even under dark conditions. Under simulated sunlight exposure, complete bacterial disinfection is achieved in just 90 s. Critically, the CAP mask displays minimal temperature elevation after 3 h of winter sunlight exposure, ensuring no thermal discomfort or harm during routine outdoor use. Additionally, it retains high filtration efficiency and outstanding reusability. The work addresses the critical need for masks that balance protection, antibacterial functionality, and sustainability across multi‐scenario daily applications (indoor and outdoor), offering an innovative strategy for developing real‐time, high‐performance protective equipment.