tailieunhanh - Synthesis and catalytic activity of branched gold nanoparticles in aqueous medium

A simple method for the preparation of multi–branched gold nanoparticles from an aqueous solution of silver seeds, cetyl-trimethylammonium bromide (CTAB), HAuCl4, and Pluronic F–127 was described. It was found that morphologies and sizes of gold nanostructures (AuNPs) depended strongly on such experimental parameters as concentrations of Pluronic F–127 and Au3+ . The products were characterized by transmission electron microscopy (TEM). Interestingly, the multi – branched AuNPs were found to serve as an effective catalyst for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of NaBH4. Kinetic data have been obtained from monitoring the concentrations of 4- NP and BH4 ‒ by UV‒vis spectroscopy. | Vietnam Journal of Science and Technology 55 (5B) (2017) 227-235 SYNTHESIS AND CATALYTIC ACTIVITY OF BRANCHED GOLD NANOPARTICLES IN AQUEOUS MEDIUM Phan Ha Nu Diem1, 2, *, Tran Thai Hoa2, Tran Thuc Binh2 1 Dong Nai University, 4 Le Quy Don, Tan Hiep Ward, Bien Hoa city, Dong Nai 2 College of Sciences, Hue University, 77 Nguyen Hue, Hue city * Email: phannudiem@ Received: 26 September 2017; Accepted for publication: 7 October 2017 ABSTRACT In this article, a simple method for the preparation of multi–branched gold nanoparticles from an aqueous solution of silver seeds, cetyl-trimethylammonium bromide (CTAB), HAuCl4, and Pluronic F–127 was described. It was found that morphologies and sizes of gold nanostructures (AuNPs) depended strongly on such experimental parameters as concentrations of Pluronic F–127 and Au3+. The products were characterized by transmission electron microscopy (TEM). Interestingly, the multi – branched AuNPs were found to serve as an effective catalyst for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of NaBH4. Kinetic data have been obtained from monitoring the concentrations of 4NP and BH4‒ by UV‒vis spectroscopy. Keywords: multi – branched gold nano, Pluronic F-127, catalytic activity. 1. INTRODUCTION Gold is a noble metal that has been employed in several applications throughout the human history due to its properties. Actually, gold in the nanoscale is important investigation field for their unique and distinctive spectral properties. Gold nanoparticles (AuNPs) have stimulated a great interest in many areas such as catalysis [1 - 3], biological and chemical sensing [4 - 6], antimicrobial [7 - 8], electrochemical [9 - 10], surface-enhanced Raman spectroscopy [11 - 13], cancer therapy and drug delivery [4, 14]. The studies on the functionalization of spherical gold nanoparticles, growth of other shapespecific gold nanoparticles has also been an active area of research interest in the past few .