Synthesis of small-sized gold nanorod using catechol as a reducing agent

Facile preparation of small gold nanorod with controllable and large surface plasmon resonance band is of great value for applications in especially the biomedical and sensing fields. In this work, we propose that without addition of additive to complicate the experimental system catechol of a very weak reducibility can be used as reducing agent for seed-mediated synthesis of gold nanorod. Under a temperature of 40 °C and a catechol concentration of 17.5 mM, monodisperse gold nanorod with a high shape yield, a largest plasmon wavelength of 918 nm, and especially a small diameter of 9.8 nm can be acquired simultaneously. A good tune over the plasmon wavelength is also shown by varying the amount of silver ion. Besides, the effects of experimental parameters including silver ion, cetyltrimethylammonium bromide, gold seed and catechol have also been carefully studied, and the morphological and structural evolutions of the particle have been discussed based on reported growth mechanism.