Sustained virucidal functionality in practical-scale polymer matrices enabled by visible light-responsive CuxO–TiO2 photocatalyst

The COVID-19 pandemic has highlighted the urgent need for durable and highly effective virucidal materials. This study presents a breakthrough by integrating Cu_xO–TiO₂ photocatalysts into widely used polymer matrices, such as silicone, polypropylene, and air filters, to achieve sustained antiviral functionality with practical applicability. Unlike previous studies that primarily focused on the antiviral efficacy of Cu-based photocatalysts, our study provides atomic-level insights into the regeneration of virucidal Cu_xO (x > 1) on TiO₂, strongly influenced by the local atomic structures of Cu_xO, particularly when Cu exhibits a low Cu–O coordination number (~ 3), as confirmed by X-ray absorption spectroscopy. This regeneration process is essential for high virucidal performance via interfacial charge transfer (IFCT) mechanisms. Our results show that Cu_xO–TiO₂ photocatalysts achieve an 8.67-ln reduction in viral activity within just 3 min of visible light exposure (λ > 400 nm). Furthermore, by optimizing the incorporation of Cu_xO–TiO₂ materials, we demonstrate that antiviral functionality is maintained in polymer matrices through strategic positioning of the photocatalysts near the surface. This ensures Cu_xO–TiO₂ remains accessible to light and reactants while maintaining strong polymer adhesion, which is critical for mechanical stability and durability. Not only does this polymer composite exhibit effective virucidal performance (4.28-ln reduction within 30 min), but it also ensures sustained performance (99.1% of its initial performance after 3 weeks under ambient conditions). These findings highlight the scalability and practical potential of these materials for consumer applications, significantly contributing to public health by reducing virus transmission.