Controllable Synthesis of Silver Nanoparticles Using Citrate as Complexing Agent: Characterization of Nanopartciles and Effect of pH on Size and Crystallinity

A method for the controllable synthesis of silver nanoparticles based on a complexing agent method was developed. Citric acid was used as a complexing agent. The effect of pH (1.6 to 5.17) on the size and net height (as obtained from XRD analyses) of silver nanoparticles was investigated. The nanoparticles (10 to 40 nm) were characterized using XRD, TEM, SEM, EDX, UV-Vis spectroscopy and TG/DTG instrument. It was found that pH has a significant influence on both size and crystallinity of the nanoparticles. This is due to the effect of pH on the distribution of citrate ion species which in turn affects the size and crystallinity of the nanoparticles. Increasing the pH value enhances the percentage of [citrate3-] ion species which allows lower size and higher crystallinity of the nanoparticles. Thus, we were able to develop a method for the controllable synthesis of nanoparticles based on the pH.