Bimetallic magnetic nanoparticles dispersed in glycerol: An efficient hydrophilic catalyst for the reduction of 4‐nitrophenol

Abstract

A one‐pot, ecologically friendly method for the preparation of Fe/Ni, Fe/Co and Co/Ni bimetallic magnetic nanoparticles (MNPs) was reported, using glycerol as both a solvent and reducing agent. Six different bimetallic MNPs by varying the proportions of transition metals, namely, Fe, Co and Ni were synthesized by the chemical reduction method. The catalytic efficiency of the synthesized nanoparticles (NPs) was explored for the reduction of 4‐nitrophenol, and the reaction rate for different catalysts was systematically analysed. Especially, glycerol‐Fe/Co (1:3) bimetallic nanoparticles as a magnetically recoverable catalyst had higher catalytic activity than the other bimetallic nanoparticles for the reduction of 4‐nitrophenol to 4‐aminophenol in the presence of sodium borohydride. The reduction process was monitored by UV–visible spectroscopy, and the reaction was complete within 8 min. The kinetic study shows 99% conversion of 4‐nitrophenol to 4‐aminophenol, and the rate constant is 0.593 min−1. Furthermore, the glycerol‐Fe/Co (1:3) MNPs were retrieved from the reaction mixture and subsequently utilized in five consecutive cycles, demonstrating both the reusability and durability of the NPs as a catalyst. This research was remarkable for its fast reaction kinetics, simplified one‐pot conversion of 4‐nitrophenol to 4‐aminophenol without the need for mechanical or magnetic stirring and in‐depth study of six bimetallic MNPs' catalytic properties in nitro reduction. These findings explored the potential benefits of bimetallic magnetic NPs for the synthesis of 4‐aminophenol products.