چکیده (انگلیسی):

In this work, spherical Ag and Au nanoparticles, primarily below 10 nm in diameter, were synthesised by
contacting biological extracts from the vascular plant Citrus limon with aqueous Au3+ and Ag+ solutions
at ambient temperature. The chemical constituents of the plant extract acted as reducing, capping and
stabilising agents, and nanoparticle size and shape could be tuned by adjusting the pH of the extract
suspension. Au nanoparticles synthesised at pH = 7 and Ag nanoparticles synthesised at pH = 11 were
monodisperse and well-defined. Thin films of these Au and Ag nanoparticles were coated onto TiO2 by
colloidal deposition and the resulting composites were tested as catalysts for the degradation of an organic
dye. 1 wt% Au/TiO2 and Ag/TiO2 composites were at least as active as M/TiO2 composites prepared by
reduction with NaBH4