Effect of the pH value on the synthesis of silver nanoparticles in an aqueous cysteine–silver solution

Abstract

Silver nanoparticles are synthesized in the medium of an aqueous cysteine–silver solution at different рН values using sodium borohydride as a reductant. Dynamic light scattering, electron spectroscopy, and transmission electron microscopy are applied to find that the size and stability of nanoparticles in this system depend on рН, which is regulated by alkali, and on the concentration of the cysteine–silver solution. Under certain conditions, it is possible to obtain a unimodal distribution for silver nanoparticles with an average size of ~40 nm.