In situ growth of gold nanoparticles on magnetic γ-Fe2O3@cellulose nanocomposites: a highly active and recyclable catalyst for reduction of 4-nitrophenol

Abstract

In this study, a facile synthetic method has been developed for in situ growth of Au nanoparticles (NPs) on magnetic γ-Fe₂O₃@carboxylated cellulose nanospheres using 2,2,6,6-tetramethylpiperidinyl-1-oxyl radical (TEMPO) oxide cellulose as linkage and reducing agent. The size of the as-prepared Au NPs can be tuned from 14 to 38 nm by the initial concentration of the gold salt used in the reaction mixture. Only one step was needed to synthesize the magnetic γ-Fe₂O₃@cellulose nanospheres. The formed γ-Fe₂O₃@carboxylated cellulose@Au is highly dispersible in aqueous solution and its potential as a magnetic catalyst is proved by the reduction reaction of 4-nitrophenol to 4-aminophenol. In particular, there was no visible decrease in the catalytic activity of the reused catalysts even after being recycled five times, which is preferred in terms of cost and environmental protection. Due to the absence of any other reducing agent during the proposed process, both the synthesis steps and the reaction cost were remarkably decreased, which makes it very suitable for industrial-scale production of recyclable catalysts.