Synthesis of anisotropic gold nanoparticles and their catalytic activities of breaking azo bond in sudan-1

Abstract

Here, we report the high yield synthesis of different shaped gold nano particles (AuNPs) through seed mediated growth process in aqueous medium. Shape dependent surface plasmon resonance (SPR) and the gradual shift of longitudinal SPR band are observed with increasing anisotropy of AuNPs. Structural changes during the growth processes are observed by transmission electronic microscopy (TEM). Here, spherical nano seeds are transformed into rice and dendrimer shaped nanoparticles in the subsequent four stage growth processes. Gold nanoparticles have been demonstrated to be very efficient catalysts for the cleavage of NN of sudan-1 and it is investigated by monitoring the reduction of sudan-1 in the presence of excess NaBH4. It has been observed that the reaction is first order with respect to the concentration of sudan-1 and the catalytic efficiency of dendrimer shaped AuNPs is higher than the other as synthesized AuNPs.