Synthesis and characterization of Cu, Ag and Au dendrimer-encapsulated nanoparticles and their application in the reduction of 4-nitrophenol to 4-aminophenol

Here, we report on the synthesis, characterization and catalytic evaluation of Cu, Ag and Au dendrimer encapsulated nanoparticles (DENs). Generations 4–6 of PAMAM-OH and PAMAM-NH2 were used as templating agents for the synthesis of Cu and Ag-DENs respectively. Generation 4 PAMAM-NH2 dendrimers were used for the synthesis of Au-DENs. These prepared DENs were characterized using UV visible (UV–vis) spectroscopy as well as a high resolution transmission electron microscopy (HRTEM). The catalytic activity of these DENs was evaluated on the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AMP) by sodium borohydride (NaBH4). The reaction was monitored by UV–vis spectroscopy at λ 400 nm. These prepared DENs were found to exhibit good activity for this reduction reaction.

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► Copper, silver and gold nanoparticles with narrow size distribution were prepared using a dendrimer template.
► The copper, silver and gold nanoparticles were utilized as catalysts for the reduction of 4-nitrophenol to 4-aminophenol.
► Full kinetic evaluation of the reaction was conducted.
► The mechanism appears to be Langmuir–Hinshelwood for the nanoparticle catalysed reduction of nitrophenol to aminophenol.