Self-cleaning photocatalytic activity: Materials and applications

Semiconductor materials, such as titanium dioxide, have garnered extensive interest due to their excellent self-cleaning and antibacterial properties. These materials possess desirable attributes resulting from the photocatalytically induced superhydrophilicity of the surface, permitting its employment in an array of important industrial, commercial and domestic applications. During the photochemical reaction, UV or visible light irradiates these semiconductors, promoting electrons to excited states, facilitating the generation of reactive oxygen species (ROS). These ROS degrade organic compounds and induce superhydrophilicity on the material's surface. Furthermore, the material is endowed with antibacterial activity, enhancing its effectiveness when employed in areas necessitating unsurpassed hygiene standards. In this chapter, the photocatalytically induced self-cleaning mechanism of surfaces is analysed. Focus then turns to photocatalytic materials, where titanium dioxide is discussed and developments regarding the rapid testing of self-cleaning photocatalytic activities are reviewed. The antimicrobial capabilities of photocatalytic materials are observed, while improvements in semiconductor technology involving the use of dopants are examined. Metal oxide composites of graphene and carbon nanotube hybrids are detailed and the properties of TiO₂/SiO₂ composites are explained. Examples of prominent commercial materials are discussed, as their fabrication and development can be attributed to the principle of photocatalytic self-cleaning activity.