Reaction-Diffusion Assisted Synthesis of Gold Nanoparticles: Route from the Spherical Nano-Sized Particles to Micrometer-Sized Plates

Abstract

The design of nanoparticles of desired sizes and shapes and 2D nanostructured materials is challenging and important due to their unique physical and chemical properties. One of the most common methods for the generation of metal nanoparticles is the wet synthetic route in which metal ions are reduced and the formed particles are stabilized in the liquid phase. Here we show a facile and powerful method to synthesize gold nanoparticles in a solid agarose gel utilizing the diffusion of reagents using the Turkevich method at room temperature. Our technique yields particles spatially separated by their sizes and shapes (spheres and plates) in the gel column. We have achieved 4 orders of magnitude difference in the sizes of the synthesized particles with a linearly increasing trend in the function of their spatial position. We have also generated micrometer-sized nanoplates with triangle, truncated triangle, or hexagon shapes attaining almost the length-to thickness ratio of 500, representing the magnificent power of the reaction-diffusion assisted synthesis.