Photocatalyst antiviral coatings – Covid 19
Titanium dioxide (TiO2), either in the anatase or rutile crystalline form, is a well-known photocatalyst. Upon exposure to ultraviolet light, free radicals are generated at the surface-atmosphere interface. These are highly efficient oxidizers of organic matter and can be used in sterilization, sanitation, and remediation applications. Rutile and anatase have different damage effects and contact-killing abilities. These differences become an advantage, and the creation of rutile and anatase mixtures (heterojunctions) have demonstrated higher reactivity than either single-phase material. Many manufacturing processes can produce anatase/rutile coatings, starting from powders or from gaseous precursors. However, their ability to do in-situ processing-repair-coating and scaling-up is far from demonstrated. While such processes produce thick TiO2 layers, it is known that only a thin layer (hundreds of nanometers) is required as this layer is not consumed during the free-radical generation. We propose to produce anatase/rutile nanolayers around titanium powder particles and consolidate these powders into thin coatings. These coatings would provide heterojunctions and be visible-light sensitized, thus not requiring ultraviolet light to operate, ultimately creating a surface capable of killing viruses upon contact.
