Metal catalysis with nanostructured metals supported inside strongly acidic cross-linked polymer frameworks: Influence of reduction conditions of AuIII-containing resins on metal nanoclusters formation in macroreticular and gel-type materials

Synthesis of gold nanoclusters inside strongly acidic ion exchangers, in beaded forms, is carried out under different conditions. After metallation with [Au(en)2]Cl3 and reduction with H2 in the absence of any added aqueous phase, Au0/-SO3H nanocomposites are produced that are compared with Au0/-SO3− Na+ ones obtained with NaBH4 as reductant in aqueous medium. Reduction conditions allow control of both distribution and size of the metal nanoclusters. Metal distribution inside the polymer beads appears to be quite homogeneous under the hydrogen reduction conditions and metal nanoclusters size turns out to be size-controlled in the 3–5 nm range. In the case of the action of NaBH4 in water, metal distribution inside the polymer beads appears to be quite peripheral and the metal nanoclusters turn out to be size-controlled but definitely larger, 5–7 nm, than those obtained by action of molecular hydrogen.

Graphical abstractTEM pictures of Au0 nanoparticles in the beads of ion exchangers Amberlyst BD20 after reduction of the partially dry materials with gaseous hydrogen.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of gold nanoclusters inside strongly acidic ion exchangers. ► Metallated resin beads are reduced with H2 in the absence of added water. ► Metallated resin beads are also reduced with NaBH4 in water. ► Metal distribution inside the resin beads is homogeneous when the reductant is H2. ► Metal distribution inside the resin beads is peripheral when the reductant is NaBH4.