Tuning the Growth Pattern of Triangular Silver Nanoplates from Lateral to Vertical by Secondary Metal Addition

We are presenting an easy synthetic access to the aqueous synthesis of truncated trigonal silver nanobipyramids with tunable width and height in a facile two step synthesis. We modified a synthesis that employs seed particles with twinning faults on which silver is deposited laterally along the twinning fault, leading to flat particles. The ratio of lateral and vertical growth is adjusted by the co-titration of further noble metal salts at nanomolar concentrations alongside the silver precursor. Thus, besides the edge lengths, the thickness and related aspect ratio of metal bipyramids can be tuned. By tracking the growth of the particles via their localized surface plasmon resonance position during the reaction using optical transmission spectroscopy, we present insights into the modification of the growth mechanism for truncated silver nanobipyramids.

Ferric Chloride-Induced Synthesis of Silver Nanodisks with Considerable Activity for the Reduction of 4-Nitrophenol

Silver nanodisks (AgNDs) have been successfully synthesized by using ferric chloride as an auxiliary agent in the presence of polyvinylpyrrolidone and N,N-dimethylformamide as both a solvent and a reducing agent. The mass ratio of reactants, temperature, and time were demonstrated to be the key factors determining the morphology of the product, and the conversion of Fe3+/Fe2+ ions played an important role in increasing the ratio of silver nanosheets (AgNSs). As the reaction prolonged, the etching effect of Cl- ions on the tips of AgNSs became more and more obvious, which made the obtained typical polygonal AgNSs turn into AgNDs eventually. In addition, the prepared AgNDs exhibited a considerable catalytic activity in the reduction of 4-nitrophenol.