An investigation on the use of liquid phase photo-deposition for the preparation of supported Pt catalysts

The preparation of alumina supported Pt catalysts through a photochemical approach, namely the liquid phase photo-deposition (LPPD) technique, was here investigated. LPPD Pt/gamma-Al2O3 catalysts were prepared irradiating at 25 degrees C and different wavelengths (254, 350 and 400 nm) an ethanol suspension of Pt(acac)2 containing gamma-Al2O3. Catalytic activity of so prepared samples was evaluated in the combustion of volatile organic compounds (VOC) and in the hydrogenation of propene, comparing the results with those of a conventionally impregnated Pt/gamma-Al2O3 sample. LPPD catalysts exhibited better performance, in particular in the VOC combustion, compared to the reference Pt sample. The activity was found to be substantially independent from the wavelength irradiation employed during catalysts preparation. On the basis of characterization results (TEM, H-2 chemisorption and FT-IR of chemisorbed CO) the higher activity of LPPD samples was related to the narrower particle size distribution of Pt clusters observed on these samples with respect to that of the impregnated Pt catalyst.