Blue TiO₂-Based Photocatalysis under Ambient Indoor Light for Prolonged Food Storage

Conventional food preservation techniques often require external devices, increasing costs and posing challenges in maintaining food quality. In this study, we developed blue titanium dioxide-tungsten trioxide-carboxymethyl cellulose (BTO-WO₃-CMC) photocatalyst surfaces integrated onto inert substrates for food preservation. The inclusion of CMC enhanced <i>Z</i>-scheme heterojunction formation, improving visible light absorption, as confirmed by ultraviolet-visible spectra. Sodium silicate (SS) improved adhesion between BTO-WO₃-CMC and the target substrate via hydrogen bonding. Analysis with X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy-dispersive X-ray spectroscopy (EDS) confirmed the crystalline integrity of BTO and WO₃ and a consistent coating smoothness. BTO-WO₃-CMC coatings extended the shelf life of strawberries to 14 days under ambient indoor lighting at 600 lx. Optimal preservation was achieved with a 0.01 g, 4 μm thick catalyst coating. Comparative experiments showed BTO-WO₃-CMC's superior efficacy over P25-WO₃-CMC and BTO-CMC. The coating was nontoxic in darkness and minimally reduced cell viability under room light. Antibacterial effects, attributed to reactive oxygen species (ROS) generation, were confirmed against <i>Escherichia coli</i> (<i>E. coli</i>) and <i>Staphylococcus aureus</i> (<i>S. aureus</i>). This study presents a noninvasive, device-free method to extend food longevity, presenting a promising solution to the food waste challenge.