First Correlation of Nanoparticle Size-Dependent Formation with the Ionic Liquid Anion Molecular Volume

Abstract

Stable silver nanoparticles are obtained reproducibly by hydrogen reduction of different inorganic precursors from Ag^IX salts (X = BF₄, PF₆, OTf) dissolved in the ionic liquids BMim⁺BF₄^-, BMim⁺PF₆^-, BMim⁺OTf^-, or BtMA⁺NTf₂^- [BMim⁺ = n-butylmethylimidazolium, BtMA⁺ = n-butyltrimethylammonium, NTf₂ = N(O₂SCF₃)₂, and OTf = O₃SCF₃] in the presence of n-butylimidazole (Bim) as the scavenger for the HX acid byproduct and with a narrow size distribution in the diameter range of 2.8−26.1 nm, which increases linearly with the molecular volume of the ionic liquid anion (transmission electron microscopy characterization).