TO THE COARSENING MECHANISM OF Pt NANOPARTICLES DURING SINTERING

A comparison between the generalized Chakraverty-Wagner and Lifshits-Slyozov-Wagner distributions with experimental histograms for Pt-nanocrystals has been performed according to the modified LSW theory applied to the surface (2D) and bulk (3D) systems. Pt nanocrystals were synthesized and deposited onto a plain solid substrate from the gas phase or from the liquid phase on the surface of carbon nanotubes. Good correlation between the experimental histograms and the theoretical curves proves that two mechanisms of the nanocrystals' growth (dissolution) can be involved simultaneously during the Ostwald ripening stage. One of them is controlled by diffusion, while the chemical reaction rate controls the other mechanism. Details of comparison between the experimental histograms and theoretical curves prove that growth of Pt-nanoparticles is controlled mainly by the chemical reaction rate (i.e. Wagner's mechanism) regardless of the synthesis method and the sintering conditions for nanocrystals.