Preparation of silver particles by spray pyrolysis of silver-diammine complex solutions

A novel precursor solution system, containing NH₃ as a complexing agent, was used for the production of Ag powders by spray pyrolysis. Solutions of Ag₂CO₃, Ag₂O, and AgNO₃ with NH₄HCO₃ were used in this study. Ag powders were obtained at unexpectedly low temperatures, i.e., 400°C or less. The Ag powders with a shell-like morphology were obtained from Ag₂CO₃ and Ag₂O solutions, whereas dense Ag particles of about 1 μm diameter were obtained from AgNO₃-NH₄HCO₃ solution. These morphologies are explained in terms of NH₃ release during spray pyrolysis.