Plasma sprayed functional coatings for photocatalytic application

Photocatalytic coatings for water and wastewater treatment are very promising, since a costly post-separation is not required as in the case of using photocatalytic powders. Under UV-Vis illumination electrons (e^-) in the valance band of many semiconductors such as TiO₂ jump to the conductance band that leaves positive hole (h⁺) behind. The e^-/h⁺ can take part in oxidation or reduction reactions to produce hydrogen or degrade organic compounds. Among various coating technologies, suspension plasma spraying (SPS) offers many advantages such as ease of use and flexibility in choosing process materials. In our institute, the departments of surface technology and advanced ceramics develop together highly active photocatalysts and then deposit them on surfaces by SPS. The partner institute for Sanitary Engineering, Water Quality and Solid Waste Management (ISWA) testes the photocatalysts in a pilot plant with model substances and real wastewater.