Platinum catalysts coalescence

Droplet size, however, does not directly or absolutely control particle size. For example, it was estimated that there are five PtCU ions in each water droplet in the microemulsion system of water in hexane, stabilized by the surfactant pentaethyleneglycol dodecylether [29, 32]. However, TEM analysis indicated that the platinum catalyst formed had an average diameter of 3.5 nm, which corresponds to 100-1500 metal atoms (depending on the shape of the particle). This example illustrates that the final particle is not formed inside the droplet. It is likely that the formation of catalysts via the microemulsion process proceeds by two steps (1) nucleation of the metal catalyst inside the droplet, followed by (2) aggregation of multiple nuclei via collision and coalescence of droplets to form the final nanocatalysts [29]. 

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