Ultraviolet and Titanium Dioxide Based Photocatalysis HVAC System to Eliminate COVID-19 for Occupant�s Safety & Health in Automobiles
In a photocatalytic air purifier system, the catalyst that cleans the air is typically titanium dioxide and it is energized by ultraviolet (UV) light. UV is the short-wavelength light just beyond the blue/violet part of the electromagnetic spectrum that our eyes can detect. This shortwave-length light has much more energy than ordinary, visible light�and exactly the right amount of energy to get titanium dioxide excited. Titanium dioxide is a semiconductor that covers the filter surface. Just a thin film of titanium dioxide is required at the filter surface with a substrate. When UV light shines on the titanium dioxide, electrons (negatively charged particles inside atoms) are released at its surface. The electrons interact with water molecules (H2O) in the air, breaking them up into hydroxyl radicals (OH�), which are highly reactive, short-lived, uncharged forms of hydroxide ions (OH−).