Formation process of nanocrystalline materials from x-ray diffraction profile analysis: Application to platinum catalysts

It’s well known that x-ray line profile analysis is a powerful and convenient method to probe the microstructural characteristics of nanocrystalline samples. In the literature well-documented techniques are normally used to obtain crystalline size distributions from x-ray line-broadening analysis. However, it is less considered that the shape of such size distributions may be a means to determine by which mechanism the particles have grown. A simple method is presented here to distinguish between two different growth mechanisms: the coalescence and Ostwald ripening process. An application of the method to platinum nanoparticle electrocatalysts with different size distributions, dispersed on high-surface-area carbon blacks, is discussed.