Jump to main content
Jump to site search

Issue 16, 2008
Previous Article Next Article

SERS-activating effect of chlorides on borate-stabilized silver nanoparticles: formation of new reduced adsorption sites and induced nanoparticle fusion

Author affiliations

Abstract

Changes in morphology, surface reactivity and surface-enhancement of Raman scattering induced by modification of borate-stabilized Ag nanoparticles by adsorbed chlorides have been explored using TEM, EDX analysis and SERS spectra of probing adsorbate 2,2′-bipyridine (bpy) excited at 514.5 nm and evaluated by factor analysis. At fractional coverages of the parent Ag nanoparticles by adsorbed chlorides <0.6, the Ag colloid/Cl/bpy systems were found to be constituted by fractal aggregates of Ag nanoparticles fairly uniform in size (10 ± 2 nm) and SERS spectra of Ag+-bpy surface species were detected. The latter result was interpreted in terms of the presence of oxidized Ag+ and/or Agn+ adsorption sites, which have been encountered also in systems with the chemically untreated Ag nanoparticles. At chloride coverages >0.6, a fusion of fractal aggregates into the compact aggregates of touching and/or interpenetrating Ag nanoparticles has been observed and found to be accompanied by the formation of another surface species, Ag-bpy, as well as by the increase of the overall SERS enhancement of bpy by factor of 40. The same Ag-bpy surface species has been detected under the strongly reducing conditions of reduction of silver nitrate by sodium borohydride in the presence of bpy. The formation of Ag-bpy is thus interpreted in terms of the stabilization of reduced Ag(0) adsorption sites by adsorbed bpy. The formation of reduced adsorption sites on Ag nanoparticle surfaces at chloride coverages >0.6 is discussed in terms of local changes in the work function of Ag. Finally, the SERS spectral detection of Ag-bpy species is proposed as a tool for probing the presence of reduced Ag(0) adsorption sites in systems with chemically modified Ag nanoparticles.

Graphical abstract: SERS-activating effect of chlorides on borate-stabilized silver nanoparticles: formation of new reduced adsorption sites and induced nanoparticle fusion

Back to tab navigation

Publication details

The article was received on 23 Nov 2007, accepted on 01 Feb 2008 and first published on 03 Mar 2008


Article type: Paper
DOI: 10.1039/B718178G
Phys. Chem. Chem. Phys., 2008,10, 2233-2242

  •   Request permissions

    SERS-activating effect of chlorides on borate-stabilized silver nanoparticles: formation of new reduced adsorption sites and induced nanoparticle fusion

    I. Šloufová, K. Šišková, B. Vlčková and J. Štěpánek, Phys. Chem. Chem. Phys., 2008, 10, 2233
    DOI: 10.1039/B718178G

Search articles by author

Spotlight

Advertisements