The Production of Nanoparticles: The “Top-Down” Approach, with Emphasis on Aerosol Routes, Especially Electrohydrodynamic Atomization
This chapter describes the production of platinum nanoparticles by Electrohydrodynamic Atomization (EHDA). For the production of particles, two fundamentally different main routes can be distinguished. The first one is by building them from molecules, such as in gas phase aerosol reactors. The second one is by disintegration of bigger structures into (nano)fractions. Different top-down techniques exist such as grinding, liquid atomization, lithography and etching, and others where both disintegration and building-up play a role, as in furnace evaporation/condensation. Most emphasis is paid to a very promising technique, EHDA or Electrospraying. EHDA is a method to produce very fine droplets from a liquid by using an electric field. EHDA refers to a process where a liquid jet breaks up into droplets under influence of electrical forces. The droplets produced by EHDA carry a high electric charge close to the Rayleigh charge limit.