Approaches to the Synthesis and Characterization of Spherical and Anisotropic Noble Metal Nanomaterials

The ability to tailor the shapes and sizes of inorganic nanostructures is critical for modern materials chemistry, because the intrinsic properties of most nanostructures are strongly dependent on their shapes and sizes, which can be further useful for various applications. This chapter provides an overview of the various synthesis methods of spherical and anisotropic noble metal nanomaterials. The shapes of resultant nanostructures can be controlled by manipulating different parameters, such as the crystallinity of seeds and the growth rates of different crystallographic facets. In this chapter, we discuss a number of useful parameters that can be tuned to control the formation of anisotropic silver and gold nanostructures with a specific shape in a solution-phase synthesis, using chemical and biological methods. A brief description of various synthesis methods and the characterization of the metal nanoparticles with a special emphasis on X-ray absorption measurements have been provided in order to understand the mechanistic aspects of crystal growth. Using the synthesis methods described herein, a variety of well-defined anisotropic shapes of silver and gold nanoparticles can be achieved and these methodologies can be directly extended to other metals. Keywords: nanostructures; spherical; anisotropic; gold; silver; chemical methods; biological methods; synthesis and characterization