“Cat in a bag” recycling of dendrimer encapsulated Au nanoparticles by use of dialysis membrane bag in the reduction of 4-nitrophenol: proof of heterogeneous catalysis

•Dendrimer encapsulated gold nanoparticles were synthesized.•The nanoparticles were immobilized in a membrane bag.•Nitrophenol reduction was evaluated.•No gold leaching was observed.•Nitrophenol reduction appeared to be a purely heterogeneous reaction

Generation 4 PAMAM-NH2 dendrimers were used as template to synthesize Au13- and Au100-dendrimer-encapsulated nanoparticles (Au-DENs) with an average diameter of 2.1 ± 0.3 and 3.1 ± 0.5 nm respectively. Au-DENs were characterized using various techniques. Catalytic recycling of Au-DENs using a dialysis membrane bag in the reduction of 4-NP is presented. The reduction process was primarily monitored by UV–vis spectroscopy at around λ 400 nm. The catalyst was found to exhibit a very good activity and stability even after more than 3 catalytic reaction cycles without any leaching, confirming that the reduction of 4-NP is purely a heterogeneous reaction.

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