Titania-Supported Gold Catalysts: Comparison between the Photochemical Phenol Oxidation and Gaseous CO Oxidation Performances

A series of Au/TiO₂ samples with gold loadings ranging from 0.11% to 1.26% have been prepared by deposition–precipitation, characterised by means of XRD, S_BET, XRF, TEM, XPS and DR UV–Vis techniques and tested in the gaseous CO oxidation and photocatalytic degradation of phenol in aqueous media. The catalytic performances of the solids on both reactions depend on the gold content. Besides this, the gold particle size plays a determinant role in the catalytic activity for the CO reaction, but apparently its influence on the photocatalytic activity appears to be negligible and only very small gold particles seem to participate on the photocatalytic process. On the other hand, the electronic properties of the solids, measured by its band gap energy, are a key factor in the photochemical activity but do not have a clear influence in the CO oxidation reaction.