Increasing the Efficiency of Photocatalytic Water Treatment with Titanium Dioxide Nanoparticles by Control of Crystal Shape

Photocatalysis is increasingly applied for purification of drinking water and the treatment and recycling of industrial wastewater. The most common photocatalytic material is titanium dioxide; anatase is the photocatalytically reactive phase. However, the reaction itself is inherently inefficient because only a small fraction of the incident photons is actually used in photocatalysis. Various methods have been proposed to increase the efficiency, including doping with gold to increase the photocatalytic activity and doping with nitrogen or boron to extend the useable wavelengths into the visible range. Thermodynamic modelling indicates that, while decreasing particle size increases the specific surface area of the titanium dioxide, it reduces the percentage area of the photocatalytically active {001} facets. Recent work has been directed towards the controlled growth of titanium dioxide crystals with a greater proportion of high energy facets in order to increase the photocatalytic efficiency.JRC.DDG.H-Institute for environment and sustainability (Ispra