A method for the formation of regular-shaped silver crystals through a wet chemical reaction (Tollen's reaction) is presented. The growth of the Ag crystals (size, morphology and aggregation) can be controlled via adjusting reaction conditions such as temperature and reducing agent concentrations before and during the reactions. The smaller Ag crystals (50-200 nm) were generated under the condition of limited reductive reagent (glucose), and the larger sliver crystals (˜5 μm) were the aggregated silver nano-particles (100-200 nm) produced at higher reducing agent concentrations. Most of the larger crystals were in the shape of cube or rectangular cube, and rarely, they were in clusters. The smaller crystals (aggregation of Ag atoms) were shaped in cube or/and cone, and both single crystals and clusters were formed. The presence of impurity (TiO2 nano-particles, 25-50 nm) as crystal seeds enables the 3-D growth of large, irregular-shaped Ag clusters (˜5 μm).
Ding, Xiaoling and Fries, David, "Silver crystals through Tollen's reaction" (2011). USF Patents. 388.
University of South Florida