Fe-Modified TiO ₂ Photocatalyst for Effective Indoor Bacterial Inactivation Using LED Light: Toward Safer Disinfection Technologies

Commercial TiO₂ P25 was modified with iron species using simple, mild and cost-effective synthesis conditions. The novel TiO₂-Fe material exhibits both high disinfectant activity and long stability under visible light irradiation. The bactericidal activity of the synthesized catalyst was assessed by its capability to inactivate <i>Escherichia coli</i> under both simulated solar and LED-visible light. XRD confirmed the structural integrity of the material, while diffuse reflectance spectroscopy evidenced its absorption in the visible region. Mössbauer and FTIR analysis of the TiO₂-Fe catalyst indicate that iron exists predominantly in the Fe³⁺ state in a Ti-O-Fe bond. Electrochemical studies allowed to correlate the reactivity with the conduction and valence band positions, providing insights into the production of reactive oxygen species (ROS) responsible for bacterial inactivation. A first noteworthy aspect of this study is the identified Ti-O-Fe bond in the TiO₂-Fe material, a feature that has not been previously reported in the literature. Another innovative aspect is the simplicity of the synthesis method, which employs a thermally mild and time-efficient process, thereby providing an efficient and accessible approach for enhancing photocatalytic properties. Our findings suggest that the prepared TiO₂-Fe photocatalyst holds potential for future applications in antimicrobial paint coatings designed for hospital environments, aiming to enhance infection control under indoor lighting conditions.