This invention comprises methods, for typical small nanoparticles, of removing elements distribution heterogeneity in the particle to significantly improve performance. For big nanoparticles, the performance of 3-D architecture made from the segregated nanoparticle could be further improved by increasing the elements distribution heterogeneity with proper post-treatment. Can be used in applications such as fuel cell electric cars, back up power for remote communication tower and other stationary applications.

A method for scaled-up synthesis of PtNi nanoparticles. Synthesizing a Pt nanoparticle catalyst comprises the steps of: synthesizing PtNi nanoparticles, isolating PtNi/substrate nanoparticles, acid leaching the PtNi/substrate, and annealing the leached PtNi/substrate nanoparticles, and forming a Pt-skin on the PtNi/substrate nanoparticles.

This invention could be used to make high performance PEM fuel cell catalyst. PEM fuel cell have variety application potentials such as fuel cell electric cars, back up power for remote communication tower and other stationary application. This invention fulfills the needs of high performance fuel cell catalyst with high Pt surface area and Pt loading. Compared with existing Pt/C catalyst, the Pt mass activity of catalyst made by this invention is 13 times higher, Pt loading could be controlled in a much wider range, Pt surface area could be much higher. It may also be used to make other core/shell structure with variety application potentials in catalysis.