Oxide nanoparticles

Oxide micro- and nanoparticles are ubiquitous in the natural environment. They have long been used as catalysts, but have found novel applications with the advent of nanotechnologies. From a fundamental point of view, they bridge the gap between the properties of isolated atoms or molecules and those of bulk condensed phases. They present a large spectrum of atomic and electronic structures, due to their finite size in the three dimensions of space and the fact that their atoms are nearly all surface atoms. They represent the first stages of nucleation and growth of larger size oxides, and their stability and properties which depend upon the thermodynamic conditions under which they are formed, largely impact the final product. This chapter reviews their specific properties and analyses their physical origin, both when they are produced in the gas phase, in an aqueous environment, or when cation mixing takes place.