The influence of gold nanoparticles on reduction of [Co(NH3)5Br](NO3)2 by iron(II)

Variable size (50-220 nm), intrinsically mono-dispersed, single shaped gold (Au) nanomaterials was made showing man-made replica of nature's flower like structures associated with vast kinetic activity. 220 nm Au nanopopcorns and nanoflowers have been synthesized simply by controlling the concentration of the reducing agent and reaction time. Other spherical metal nanoparticles made of platinum (Pt), Au and palladium (Pd) also show catalytic effect on the rate of the reduction of [Co(NH3)(5)Br](NO3)(2) by iron(II), which was taken as a model reaction. Their activity increases with increased loading. Catalytic activity follows the order: Pt > Au > Pd, which has been compared with that of the various Au nano-formations (popcorns and flowers). The larger Au nanopopcorns and nanoflowers induce appreciable reduction in the rate of the reaction compared to the effects of similar concentrations of the spherical nanoparticles. Graphic abstract Catalytic activity follows the order: Pt > Au > Pd, which has been compared with that of the various gold nano-formations (popcorns and flowers). The larger gold nanopopcorns and nanoflowers induce appreciable reduction in the reaction rate compared to the effects of similar concentrations of the spherical nanoparticles. [GRAPHICS] .