A novel strategy to prepare silver nanoparticles by ethanol-induced shape conversion of silver dendrites from modified galvanic replacement

The fabrications of the silver nanostructures with various shapes have been successfully conducted by using an ultrasound assisted galvanic replacement reaction (GRR) in aqueous solutions containing silver nitrate and copper sheet using PVP as stabilizer. Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) have been used to characterize the as-synthesized silver products. The results show that a variety of silver nanostructures, such as silver dendrites, the triangular, hexagonal, disk nanoplates and spherical nanoparticles, can be yielded in large scale by facilely tuning the silver nitrate concentrations, temperature and concentration of PVP in aqueous solutions. The as-synthesized silver dendrites were deposited in ethanol without any field (UV or visible light irradiation) or thermally induced activation, a significantly spontaneous evolution in morphology occurred from the fractal structure to silver nanoparticles at room temperature. Moreover, the mechanisms of the architectural reconstruction of silver nanostructures in ethanol at room temperature by self-assemble were discussed. The proposed dissolution recrystallization process induced by ethanol may be responsible for the morphological reconstructure of the as-synthesized Ag dendrites.