Green synthesis, growth and catalytic activity of silver nanoparticles

A facile green synthesis of silver nanoparticles has been developed using ascorbic acid and gum acacia as reducing agent and stabilizing agent, respectively. The present work is mainly concerned with understanding the role of reducing and stabilizing agents in the growth of silver nanoparticles. Silver nanoparticles fabricated by using ascorbic acid in a gum acacia solution show faster growth rate and exhibit a rod- and thread-like structure with an average diameter of 40–54 nm, while silver nanoparticles prepared using gum acacia as both reducing and stabilizing agent show slower growth rate, having a pseudo-spherical shape with an average diameter of 11–15 nm. The rod- and thread-structured nanoparticles exhibit a surface plasmon resonance band at 645 nm, while the pseudo-spherically shaped particles show absorbance at 424 nm. The silver nanoparticles showed a face-centered cubic crystal system as predicted from the X-ray diffraction pattern. The impact of structural variation on the catalytic properties of silver nanoparticles was also demonstrated in this work. The catalytic activity of silver nanoparticles fabricated by using the green approach was demonstrated by using methylene blue dye. The pseudo-spherical silver nanoparticles exhibit greater catalytic activity as compared to the rod- and thread-shaped silver nanoparticles.