CHAPTER 4: Role of Phenols and Phenol Derivatives in the Synthesis of Nanoparticles

In recent years, there has been intensive research into finding less expensive, non-toxic, and easier wet-chemical synthetic methods in order to control the properties of metal nanoparticles used for a variety of applications. Physical and chemical properties of nanoparticles are highly dependent on size, shape, crystallinity, and composition. Moreover, it is difficult to control nanoparticle behaviours in solution, since they have a tendency to form agglomerations due to their particular size and high surface energy and the dominant van der Waals forces present. Considerable effort has gone into finding novel strategies to produce well-tuned and stable metal nanoparticles as well as optimizing existing synthetic methods through the investigation of the reaction conditions and the pursuit of more effective reagents to reduce a variety of metal complexes. Among such reagents, phenol and its derivatives, also found in biological systems, are proven to be not only good capping agents but also efficient reducing agents that can control the relative rates between nucleation and growth well enough to achieve the desired metal nanoparticles for targeted applications. This chapter is dedicated to the different types of phenols used as reducing and stabilizing agents to produce well-defined metal nanoparticles, namely, Au, Ag, Pd, and M_xO_n nanoparticles.