3 research outputs found
On the nature of citrate-derived surface species on Ag nanoparticles: insights from X-ray photoelectron spectroscopy
Π’Π΅ΠΊΡΡ ΡΡΠ°ΡΡΠΈ Π½Π΅ ΠΏΡΠ±Π»ΠΈΠΊΡΠ΅ΡΡΡ Π² ΠΎΡΠΊΡΡΡΠΎΠΌ Π΄ΠΎΡΡΡΠΏΠ΅ Π² ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΠΈΠΈ Ρ ΠΏΠΎΠ»ΠΈΡΠΈΠΊΠΎΠΉ ΠΆΡΡΠ½Π°Π»Π°.Citrate is an important stabilizing, reducing, and complexing reagent in the wet chemical synthesis of
nanoparticles of silver and other metals, however, the exact nature of adsorbates, and its mechanism of
action are still uncertain. Here, we applied X-ray photoelectron spectroscopy, soft X-ray absorption nearedge
spectroscopy, and other techniques in order to determine the surface composition and to specify the
citrate-related species at Ag nanoparticles immobilized from the dense hydrosol prepared using roomtemperature
reduction of aqueous Ag+ ions with ferrous ions and citrate as stabilizer (Carey Lea method).
It was found that, contrary to the common view, the species adsorbed on the Ag nanoparticles are, in large
part, products of citrate decomposition comprising an alcohol group and one or two carboxylate bound to
the surface Ag, and minor unbound carboxylate group; these may also be mixtures of citrate with lower
molecular weight anions. No ketone groups were specified, and very minor surface Ag(I) and Fe (mainly,
ferric oxyhydroxides) species were detected. Moreover, the adsorbates were different at AgNPs having
various size and shape. The relation between the capping and the particle growth, colloidal stability of
the high-concentration sol and properties of AgNPs is briefly considered