Controllable biosynthesis of gold nanoparticles from a Eucommia ulmoides bark aqueous extract

•Green synthesis of gold nanoparticles using Eucommia ulmoides bark extract.•The size of biosynthesized gold nanoparticles was controllable.•The water soluble compounds act as both reducing and stabilization agents.•The as-synthesized AuNPs show excellent catalytic activity.

The present work reports the green synthesis of gold nanoparticles (AuNPs) by water extract of Eucommia ulmoides (E. ulmoides) bark. The effects of various parameters such as the concentration of reactants, pH of the reaction mixture, temperature and the time of incubation were explored to the controlled formation of gold nanoparticles. The characterization through high resolution-transmission electron microscopic (HRTEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) infer that the as-synthesized AuNPs were spherical in shape with a face cubic crystal (FCC) structure. The results from zeta potential and dynamic light scattering (DLS) suggest the good stability and narrow size distribution of the AuNPs. This method for synthesis of AuNPs is simple, economic, nontoxic and efficient. The as-synthesized AuNPs show excellent catalytic activity for the catalytic reducing decoloration of model compounds of azo-dye: reactive yellow 179 and Congo red.

Graphical abstractControllable biosynthesis of gold nanoparticles using Eucommia ulmoides.Figure optionsDownload full-size imageDownload as PowerPoint slide