TiO2-coated foams as a medium for solar catalysis

Sunlight irradiating the surface of the Earth represents a maximum input available for a solar catalytic process of 50 W_UV m⁻². We propose using high-porosity, metallic, reticulated foams as the support medium for the photocatalyst in order to improve the apparent quantum yield. The layer of TiO₂ was applied by dip-coating. The measurement of the degradation kinetics was carried out on a model target molecule, 2,4 dichlorophenol, at an initial concentration of 10 mg l⁻¹. The aim was to assess the efficiency of the foams as a photocatalytic media compared to that of a suspension of catalytic powder (Degussa P25) and the flat 2D support (Ahlstrom cellulose media). The apparent quantum yield of the foam scaffold carrying the TiO₂ was high, showing that, as with the powder suspension, foam makes good use of the UV rays to break down molecules. It is noteworthy that the apparent quantum yield of the foam tended towards that observed for suspensions which form the ideal support thanks to their optimal ability to harness the light.