Synthesis of Gold Nanoplates with Bioreducing Agent Using Syringe Pumps: A Kinetic Control

Anisotropic Au nanoplates are particularly important owing to their unusual properties. Herein, we describe a plant-mediated bioreduction method to increase the yield of Au nanoplates and shorten the reaction time through a kinetically manipulated procedure. More specifically, the reduction rate was controlled by modulating experimental factors such as the addition mode and rate of the feed solutions, the temperature, and the pH based on a syringe-pumps apparatus. The dimensions of the obtained Au nanoplates were measured using TEM and AFM. The single-crystalline structure was demonstrated by HRTEM, SAED, and XRD. The results of XPS, FTIR, and TG analyses indicated strong affinity of the biomolecules binding to the Au nanoplate facets. In particular, the nanoplate films exhibited strong surface plasmon absorbance in the near-infrared range of 700–3000 nm, vital for optical applications. Furthermore, we propose a mechanism for this formation following the time-resolved studies.