Size-tunable synthesis of high-quality gold nanorods under basic conditions by using H2O2 as the reducing agent

We report a novel method for wet synthesis of gold nanorods (GNRs) with H2O2 as the reducing agent. Our method filled the gap of synthesizing GNRs under basic conditions through a seed-mediated method. The XRD data and HRTEM image show that GNRs have face-centered cubic structures and the growth of GNRs is along the [001] direction. Moreover, we investigated the impacts on GNR synthesis through changing the experimental parameters, including the added amounts of NaOH, the H2O2/Au3+ ratio, and the concentration of AgNO3, by UV-Vis spectroscopy and TEM. It is found that the longitudinal localized surface plasmon resonance peak of GNRs can be easily tuned and the maximum of 981 nm can be achieved. The GNRs prepared by our method have well-controlled morphology, high purity and improved monodispersity. The quality of GNRs is no longer sensitive to the concentration of the reducing agent, and excellent GNRs can be prepared even when the H2O2/Au3+ ratio is adjusted to 300 : 1. This new GNR preparation method provides an approach to obtain high-quality GNRs with different sizes, which is expected to find wide applications in various fields, especially those requiring basic conditions.