Catalytic performance of Ag, Au and Ag-Au nanoparticles synthesized by lichen extract

Abstract

In the present study, the green chemistry approach for the biosynthesis of Ag, Au and Ag-Au bimetallic nanoparticles (NPs) was applied using lichen extract [Cetraria islandica (L.) Ach.]. The lichen extract acts both as a reducing and stabilizing agent. The monometallic and bimetallic NPs were characterized by transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The results showed that NPs were successfully synthesized and the prepared structures were generally spherical. The synthesized nanostructures exhibited excellent catalytic activities towards reduction of nitrophenols (4-nitrophenol; 4-NP) to aminophenols (4-aminophenol; 4-AP) with sodium borohydride (NaBH4). It was determined that bimetallic NPs exhibit more effective catalytic activity than monometallic Ag and Au nanostructures. This is the first report on 4-NP reduction with Ag, Au and Au-Ag NP catalysts prepared by lichen extract.

Lichens—A Potential Source for Nanoparticles Fabrication: A Review on Nanoparticles Biosynthesis and Their Prospective Applications

“…Furthermore, lichen extract has been established as an efficient reducing and capping agent for NPs due to the vast abundance, rapid growth, and most importantly, environmental sustainability of these organisms [ 143 ]. The functional groups of secondary metabolites from lichen extracts are instrumental in preventing aggregation of NPs and hence improve the fabrication and stabilization of NPs [ 144 ]. Lichen-based NPs show great potential as therapeutic agents, serving as antimicrobials, antidiabetics, and antioxidants [ 145 , 146 ].…”

“…Bimetallic NPs (Au–Ag NPs) were extracellularly synthesized using Cetraria islandica [ 144 ]. In brief, 1 mL lichen extract was mixed with 10 mL of 1.5 mm HAuCl 4 and AgNO 3 solutions and 0.5 m NaOH solution (pH 10) and incubated for 30 min at 80 °C under continuous mixing and stirring conditions.…”

“…Çıplak et al conducted the first study on the catalytic activity of biogenic monometallic NPs (Ag- and Au-NPs) and bimetallic NPs (Au-Ag NPs) synthesized by Cetraria islandica [ 144 ]. Bimetallic NPs showed higher catalytic activity than monometallic NPs for the reduction of nitrophenols (4-nitrophenol; 4-NP) to aminophenols (4-aminophenol; 4-AP) with sodium borohydride (NaBH 4 ).…”

A Mini-Review on Lichen-Based Nanoparticles and Their Applications as Antimicrobial Agents

“…Nanoparticles derived from metals and their oxides such as silver, gold, titanium, cadmium, iron, zinc, and copper have reportedly been synthesized using many lichens (Mie et al, 2014;Çıplak et al, 2018;Bhat, 2018;Alavi et al, 2019;Gandhi et al, 2019). Many of these lichen-based nanoparticles have been reported to exhibit antimicrobial bioactivity against several bacteria and fungi, which could be attributed to their ability to disintegrate the microbial membrane, oxidation of various cellular components, and generation of hydroxyl radicals (Ruparelia et al, 2008;Marambio-Jones and Hoek, 2010).…”

Fabrication and characterization of polymer-based nanocomposite membrane modified by magnetite nanoparticles for Cd 2+ and Pb 2+ removal from aqueous solutions

“…The green synthesis of NPs from natural biological resources such as lichens is an inexpensive, efficient, eco-friendly, chemical-free, and sustainable method [16]. In the past few years, some types of lichens [17], algae [18], fungi [19], and bactericidal agents [20] have been utilized to synthesize non-toxic and useful metallic NPs. In this study, the synthesis of iron oxide NPs by the plant extract of lichen Ramalina sinensis (RS) was explored.…”