CHAPTER 1. Reducing Agents in Colloidal Nanoparticle Synthesis – an Introduction

During the last four decades, the use of nanoparticles has become an important topic in the fields of nanotechnology. Their potential applications in high diversity areas of research make them practically irreplaceable tools in medicine, biomaterials, catalysis, etc. There are countless methods to afford nanoparticles; however, the reduction of ionic species into atomic material is probably one of the most used pathways to generate nanoparticles in a consistent and controlled manner. In the chemical and biological bottom–up approach, the soluble material is reduced to insoluble atomic clusters which grow until a nanoparticle dispersion occurs. For carrying out these kinds of processes, reagents from multiple sources and different intrinsic properties can be used, thanks to their redox potential. This introductory chapter aims to describe the main redox agents used for the colloidal nanoparticle synthesis, from the most classical to the newest chemistry pathways.