Silver nanoparticle aggregates by room temperature electron reduction: preparation and characterization

Abstract

A step-by-step room temperature electron reduction has been developed in this work to prepare silver nanoparticle aggregates on anodic aluminium oxide (AAO) substrate. No chemical reducing agent is needed. The aggregates are formed by silver nanoparticles with a particle size of about 3 nm. The colour of the silver nanoparticle aggregates can be adjusted from yellow (with small Ag loading) to dark (with high Ag loading). Especially, the colour of these aggregates depends on the size of the Ag nanoparticle aggregate, rather than on the size of the single Ag nanoparticles. The silver aggregate/AAO composites show an outstanding surface plasmon resonance (SERS) characteristic. The Raman enhancement factor reaches as high as 1.054 Â 10 7 . The silver nanoparticle aggregates can be dispersed as Ag nanoparticles within a liquid solution with the removal of the substrate under the assistance of ultrasonic dispersion.The silver nanoparticle aggregates obtained by this step-by-step electron reduction provide a convenient and sustainable means for the storage of metal nanoparticles.

Highly Active and Stable Pt–Pd Alloy Catalysts Synthesized by Room‐Temperature Electron Reduction for Oxygen Reduction Reaction

“…According to our previous studies[19a,20a] and theoretic studies by Neyts and co‐workers, when additional metal precursor ions are introduced to metal‐support material between two electron reduction processes, these ions will tend to adsorb on the metal nanoparticles instead of the support due to the lower surface energy. After the second electron reduction, these additional ions will be reduced to form the alloy or aggregates with the original metal nanoparticles.…”

“…Herein, we report the synthesis of highly active and stable carbon‐supported Pt–Pd alloy catalysts for PEMFCs cathode using room‐temperature electron reduction with argon glow discharge as electron source . Glow discharge is well known as a conventional cold plasma phenomenon with highly energetic electrons, with which the reduced metal NP shows small size, strong interaction with the support and high catalytic property . This method needs neither chemical reducing agents nor protective chemical nor dispersing agents.…”

Chemical and electrochemical characterization of Nafion containing silver nanoparticles in a stripe-like distribution

“…For the other nanocomposites (N2, N3, N4), the percentage of AgNO 3 was marginal compared to metallic silver, so it would not have been detected by XRD either because the amount of this compound were too low to show peaks or it were not crystalline. 40 …”

“…Since Ag peaks are broadened, it is possible to affirm that Ag(I) ions were successfully reduced to Ag-NPs at high extent. [40][41][42][43] Besides, the analysis by XPS provided more detailed information on silver speciation and location, since this technique is surface sensitive and gives qualitative and quantitative information of the elements present in a thickness less than 10 nm through the study of the binding energy. 44 As it can be observed in Fig.…”

The interaction of fluorescent Pyronin Y molecules with monodisperse silver nanoparticles in chloroform

“…The absorption spectrum of PyY (1.0x10 -5 M) in chloroform had two absorption bands appeared at 553 nm (monomer) and at 540 nm (H-dimer) (Figure 2). The surface plasmon absorption of Ag NPs at 431 nm was observed [24] due to the SPR property of Ag NPs depending on their size, shape and structure. At the diluted Ag NPs concentrations, the absorption spectrum of PyY was identical to its spectrum obtained in pure chloroform ( Figure 4).…”