Large scale synthesis and formation mechanism of silver nanoparticles in solid-state reactions at ambient temperature

•AgNPs were prepared by solid state reaction at ambient temperature.•Only silver nitrate and ascorbic acid were needed in this reaction.•The size of the AgNPs can be tuned conveniently.•Formation mechanism of the AgNPs was investigated.

A one-step strategy for preparing Ag nanoparticles (AgNPs) on large scale is demonstrated successfully, based on solid-state reactions at ambient temperature. The environmentally friendly synthesis can be achieved by simply grinding AgNO3 and ascorbic acid (AA) for about 30 min without adding any solvent and organic protectors. The size of AgNPs can be readily controlled by adjusting the reaction parameters such as AgNO3/AA molar ratio and reaction time. The nanostructures of AgNPs and their formation mechanism have been also investigated with XRD, FTIR, FESEM, HRTEM and HPLC–MS. It was found that AA can reduce Ag+ into Ag0 to form AgNPs directly in accompanying with its first oxidation into 2,3-diketogulonic acid (2,3-DKG) and then a series of fragmentary species of 2,3-DKG.