Polymer microgels for the stabilization of gold nanoparticles and their application in the catalytic reduction of nitroarenes in aqueous media

• Published in: RSC advances Vol. 12; no. 9; pp. 515 - 5117
• Main Authors: Arif, Muhammad, Shahid, Muhammad, Irfan, Ahmad, Nisar, Jan, Wu, Weitai, Farooqi, Zahoor H, Begum, Robina
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 10.02.2022; The Royal Society of Chemistry
• Subjects: Aqueous solutions; Catalysis; Chemical reduction; Chemistry; Chloroauric acid; Fourier transforms; Free radical polymerization; Free radicals; Gold; Infrared spectroscopy; Microgels; Nanoparticles; Nitrophenol; Polymers; Polystyrene resins; Reducing agents; Spectrum analysis
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d1ra09380k

Polymer microgels containing a polystyrene core and poly( N -isopropylmethacrylamide) shell were synthesized in aqueous media following a free radical precipitation polymerization. Au nanoparticles were fabricated into the shell region of the core-shell microgels denoted as P(STY@NIPM) by the in situ reduction of chloroauric acid with sodium borohydride. Various characterization techniques such as transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-visible) and Fourier transform infrared spectroscopy (FTIR) were used for the characterization of Au-P(STY@NIPM). The catalytic potential of Au-P(STY@NIPM) toward the reductive reaction of 4-nitrophenol (4NP) under various reaction conditions was evaluated. The Arrhenius and Eyring parameters for the catalytic reduction of 4NP were determined to explore the process of catalysis. A variety of nitroarenes were converted successfully into their corresponding aminoarenes with good to excellent yields in the presence of the Au-P(STY@NIPM) system using NaBH 4 as a reductant. The Au-P(STY@NIPM) system was found to be an efficient and recyclable catalyst with no significant loss in its catalytic efficiency. A core-shell microgel system was synthesized and used as a micro-reactor for the synthesis of gold nanoparticles. The resulting hybrid system has the ability to catalyze the reduction of various nitroarenes in aqueous media.