Green synthesis of gold and silver nanoparticles using gallic acid: catalytic activity and conversion yield toward the 4-nitrophenol reduction reaction

Abstract

In the present report, gallic acid was used as both a reducing and stabilizing agent to synthesize gold and silver nanoparticles. The synthesized gold and silver nanoparticles exhibited characteristic surface plasmon resonance bands at 536 and 392 nm, respectively. Nanoparticles that were approximately spherical in shape were observed in high-resolution transmission electron microscopy and atomic force microscopy images. The hydrodynamic radius was determined to be 54.4 nm for gold nanoparticles and 33.7 nm for silver nanoparticles in aqueous medium. X-ray diffraction analyses confirmed that the synthesized nanoparticles possessed a face-centered cubic structure. FT-IR spectra demonstrated that the carboxylic acid functional groups of gallic acid contributed to the electrostatic binding onto the surface of the nanoparticles. Zeta potential values of -41.98 mV for the gold nanoparticles and -53.47 mV for the silver nanoparticles indicated that the synthesized nanoparticles possess excellent stability. On-the-shelf stability for 4 weeks also confirmed that the synthesized nanoparticles were quite stable without significant changes in their UV-visible spectra. The synthesized nanoparticles exhibited catalytic activity toward the reduction reaction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride. The rate constant of the silver nanoparticles was higher than that of the gold nanoparticles in the catalytic reaction. Furthermore, the conversion yield (%) of 4-nitrophenol to 4-aminophenol was determined using reversed-phase high-performance liquid chromatography with UV detection at 254 nm. The silver nanoparticles exhibited an excellent conversion yield (96.7-99.9 %), suggesting that the synthesized silver nanoparticles are highly efficient catalysts for the 4-nitrophenol reduction reaction.

A green deposition method of silver nanoparticles on textiles and their antifungal activity

“…The results obtained of this study are similar to the previous studies that also investigated the UV-vis spectra of AgNPs in the range 350-400 nm [23]. Several studies have confirmed the correlation between the UV-vis spectrum and properties of AgNPs [24][25][26][27]. A single peak in the UV-vis spectrum can be correlated with uniform spherical AgNPs [28][29].…”

Silver-pig skin nanocomposites and mesenchymal stem cells: suitable antibiofilm cellular dressings for wound healing

“…In this green process, oxidation reaction of phenol groups in gallic acid is responsible for silver ions reduction (Additional file 1 : Figure S1). Then, produced quinoid compounds with a ketoenol-system are adsorbed on the surface of silver nanoparticles accounting for its stabilization [ 36 , 37 ]. Additionally, gallic acid molecules on the surface of nanoparticles form hydrogen bonds between neighboring molecules further stabilizing the AgNPs [ 38 ].…”

Highly stable gold nanoparticles green-synthesized by upcycling cartilage waste extract from yellow-nose skate (Dipturus chilensis) and evaluation of its cytotoxicity, haemocompatibility and antioxidant activity

“…Excellent reviews were reported by the author about the utilization of plant extracts and polysaccharides in the green synthesis of AuNPs and AgNPs [12]. We have used plant extracts (Artemisia capillarys [13], Leonurus japonica [14], Polygala tenuifolia [15,16], Caesalpinia sappan [17,18], Bupleurum falcatum [19], and Galcinia mangostana [20]), invertebrate animal extracts (Eisenia andrei and Achatina fulica) [21], pure compounds from plant origins (resveratrol [22], tannic acid [23,24], rosmarinic acid [25], caffeic acid [26], chlorogenic acid [27], gallic acid [28] and catechin [29]) and pure compounds from animal origins (heparin [30], chondroitin sulfate [31,32], acharan sulfate [31] and sialyllactose [33]). Medicines, such as ampicillin [34], vancomycin [35] and ethambutol [36], were also utilized as reducing agents.…”