Preparation and Optical Properties of Nanocomposites Containing Palladium Within Mesoporous Silica via Sol-Gel Chemistry

The preparation and optical characterization of nanocomposites comprised of palladium into mesoporous silica are presented in this paper. Introduction of palladium was conducted through two different routes involving the sol-gel technique. In the first route, monolithic porous silica produced by hydrolysis of alkoxides in advance was then impregnated into the concentrated solution containing palladium precursor, and the nanocomposite was manufactured after a sequent thermal treatment. In the another route, a mixture made with the alkoxides and palladium precursor added in water was stoichiometrically prepared with the hydrolysis and condensation reactions, resulting in a formation of the composite silica gel. The introduced palladium particle was subjected to the matrix, varied with the composition and found to be 5–10 nm in scale. The optical absorption measurements show that the edges were red-shifted to a certain extent with an increase in the composition and heated temperature. The changes can be responsible for the interactions between the matrix and the introduced phase. IR characterization for the monolithic silica and the nanocomposites was also performed for the further explanation.