Direct and sensitized liquid phase photodeposition for the preparation of alumina supported Pd nanoparticles for applications to heterogeneous catalysis

Different photochemical approaches have been investigated to prepare alumina supported Pd nanoparticles to be used as heterogeneous catalysts. The employed techniques were: (i) direct photodeposition, (ii) sensitized photodeposition, and (iii) photodeposition in the presence of a protecting agent (polyvinylpirrolidone). The sensitized photodeposition with acetone resulted to be the most proper technique, allowing to obtain, in very short irradiation time, Pd particles homogeneously distributed over the support surface, with a very narrow and symmetrical monomodal distribution centered at 4–5 nm, found to be appropriate for the deep oxidation of methanol.