First correlation of nanoparticle size-dependent formation with the ionic liquid anion molecular volume.

Stable silver nanoparticles are obtained reproducibly by hydrogen reduction of different inorganic precursors from AgIX 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).