Polyacrylate-Assisted Size Control of Silver Nanoparticles and Their Catalytic Activity

Abstract

In this work, a simple one-step method of silver nanoparticle (NPs) preparation with controlled size is introduced. Silver NPs were prepared by reduction of [Ag(NH 3 ) 2 ] + complex cation by D-maltose in the presence of low concentrations (1 × 10 −10 mol/L to 1 × 10 −7 mol/L) of high-molecular-weight poly(acrylic acid) (PAA). This modification of the reduction reaction results in managing of the prepared silver nanoparticles' size in the range from 28 nm (the reaction system without PAA) to 77 nm (system with the highest used PAA concentration). The presence of poly(acrylic acid) influences both nucleation process and also the subsequent stage of nanoparticle growth. The rate of nuclei formation by homogeneous nucleation is affected by PAA due to the formation of the strong complex with silver ions which results in a prolongation of the initiation phase of the reduction process proportionally to PAA concentration. The formation of the adsorption layer of PAA on the surface of the emerging silver nuclei prevents the direct contact between silver ions and nuclei, which is necessary for continuation of the nuclei growth via heterogeneous catalytical mechanism. Because of this restriction, the silver nuclei grow up to their final size by the aggregation mechanism. The as-prepared silver NPs were tested as efficient catalysts for redox reactions. For this purpose, a model reaction, the reduction of organic dye by sodium borohydride was used. The mechanism of this reaction is discussed using the Langmuir−Hinshelwood model of heterogeneous catalysis.

Comparison of 20 nm silver nanoparticles synthesized with and without a gold core: Structure, dissolution in cell culture media, and biological impact on macrophages

“…An image of the particle formation and capture process shown in Fig. 6 in their paper 84 appears similar to our Figs. 3(b), 3(c), 3(e), and 3(f).…”

“…53,74,75,80,82 We note particularly that Akaighe et al 80 observed formation of AgNPs by the reduction of Ag ions in the presence of humic acids; Goswami et al 83 observed protein enabled nanoparticle growth; Pan aček et al 84 used a high molecular weight polymer to nucleate and control the size of Ag nanoparticles. They found the presence of poly(acrylic acid) (PAA), which forms a strong complex with Ag þ s, influenced both nucleation and growth of nanoparticles and that the size of the particles formed was larger when the concentration ratio of PAA/Ag was higher.…”

On Metal Segregation of Bimetallic Nanocatalysts Prepared by a One-Pot Method in Microemulsions

“…One of the fundamental attractions of metallic nanoparticles is the improvement of catalysts [8,9] due to the obvious increase in the active surface area compared with existing metal particles. As an example, a reduction in Pt content of the Pt-based catalysts would be very interesting in the automotive industry.…”

“…One must keep in mind that not just the final metal, but also the metal precursor, influences the reduction rate, because the reduction potential of a metal is a characteristic feature of the concrete metal precursor. However, only the couple Pt-Pd (see experiments [9][10][11] It is interesting to point out that only alloys were obtained for ∆ε 0 < 0.20 V (see Table 1, experiments 1-10). That is, it seems that a minimum difference in reduction rates ∆ε 0 ≥ 0.20 V is required to obtain a core-shell architecture, and this result cannot be modified by changing the microemulsion.…”

Facile Synthesis of Silver Nanoparticles Using a Novel Benzenethiol Derivative: Addition Effect of Cationic Surfactants

“…In particular, AgNps have been successfully used in many fields such as catalysis, sensing, nanophotonics, optoelectronics, biosensing and molecular diagnostics [4][5][6][7][8][9][10]. Advanced research led to their simple, facile and high performance fabrication with manipulated morphology and size [11][12][13].…”