Metal palladium dispersed inside macroporous ion-exchange resins: textural characterization and accessibility to gaseous reactants

Commercial macroporous ion-exchange resins (Lewatit SPC 118 and UCP 118) were used to support Pd metal by a two step ion-exchange and reduction procedure. The textural features of the resins under solid-liquid conditions were determined by means of ISEC, ESR and PGSE-NMR measurements. TEM characterization of the obtained Pd/resin composite showed the presence of uniformly sized Pd crystallites located at the macropore “surface”. Pulse chemisorption analysis gave evidence for the lack of accessibility of the crystallites when the resin composite is in the dry state, thus suggesting that the metal particles are in fact embedded in a dry gel-type resin layer at the “surface” of the macropores and therefore practically unaccessible to the molecules of a gaseous phase.