UV / visible sol gel W–TiO2 photocatalytic coatings for interior building surfaces

This article describes the synthesis of tungsten doped (W–TiO2) nanoparticles and their incorporation into a coating to improve the air quality inside buildings. W–TiO2 was prepared using a sol-gel synthesis route incorporating 1%, 2.5% and 3% tungsten in TiO2. Coatings containing the nanoparticles were produced using a water/alcohol liquid phase containing a polyurethane binder and applied to the surface of medium density fibreboard (MDF). Photocatalytic activity of unbound nanoparticles was studied using methylene blue degradation to evaluate liquid/solid interface reactions and NOx degradation to study gas/solid interfacial reactions. The coatings containing the nanoparticles were applied onto the surface of MDF and evaluated using Ink Intelligent indicator dyes. In the tests photocatalytic activity under visible light of all W–TiO2 concentrations exhibited a higher activity compared to the commercially available Degussa P25. This paper has demonstrated for the first time that polyurethane W–TiO2 coatings can be effectively applied to MDF and exhibit activity in visible light.