Preparation of ceria and titania supported Pt catalysts through liquid phase photo-deposition

The preparation of supported platinum catalysts through a photochemical approach, namely the liquid phase photo-deposition, has been investigated. Pt catalysts were prepared by irradiating at 25 degrees C and 254 nm an alcohol solution of platinum acetylacetonate complex, where two different supports (ceria or titania) were successively suspended. The prepared catalysts were characterized by TEM analysis and tested for the catalytic deep oxidation of two representative volatile organic compounds, namely toluene and acetone. Results were compared with those from Pt samples prepared by a conventional impregnation technique. It was found that the ceria supported Pt sample prepared by the photochemical approach exhibits much better performance in the combustion of both acetone and toluene, compared to the corresponding impregnated catalyst. A similar trend but to a lesser extent was observed on the Pt/titania series. These results were rationalized on the basis of the different distribution of Pt particles on the support, catalysts prepared by impregnation exhibiting both local massive Pt aggregates and very small Pt particles, samples prepared by photo-deposition showing instead Pt nanoparticles with a homogeneous and narrow size distribution, with diameters in the range of 1.6-2 nm, regarded as appropriate for the deep oxidation of volatile organic compounds.