Amphiphilic dendrimer stabilized Ag, Pd and Pt homogeneous nanoparticle catalysts and their catalysis for the reduction of methyl orange

Two different amphiphilic poly(propyleneimine) dendrimers (APPI-G2-(N⁺CΓ)_x) were synthesized by reductive methylation of poly(propyleneimine) dendrimer with HCOOH/HCHO and thus yield methylated dendrimer having eight dimethyl amino end groups. This in turn was converted into amphiphilic form via quaternization with 1-bromooctane. By varying the mole ratio of alkyl bromide to dendrimer, averages of 5&10 quaternary ammonium groups were generated individually. The prepared amphiphilic dendrimer templates were used individually and stabilized the Ag, Pd and PtNPs. The resultant homogeneous nanoparticle catalysts were characterized with UV-Vis, FESEM and EDS techniques. The catalytic activity of the APPI-G2-(NCΓ)_x -NPs were examined through reduction of methyl orange under pseudo-first order condition at ambient temperature. The catalytic efficiency of these catalysts were found in the order of APPI-G2-(N⁺CΓ)₅ -PdNPs >; APPI-G2-(N⁺CΓ )₅ -AgNPs >; APPI-G2-(N⁺CΓ)₅ -PtNPs.