Scale-Up and Continuous Synthesis of Pt-Ni Nanocrystals as Oxidation Reduction Reaction Electrocatalysts for Proton-Exchange Membrane Fuel Cells (PEMFCs)

We investigate several synthetic routes to obtain different octahedral Pt-Ni nanocrystals with remarkable activities toward the oxygen reduction reaction (ORR), most notably Pt₃Ni phase. Growing demand for hydrogen-based clean energy has prompted the development of high-performance proton exchange membrane fuel cells (PEMFCs) that convert hydrogen fuel to electricity directly. While a variety of compositions in Pt-Ni system are feasible according to the Pt-Ni phase diagram, Ni-rich Pt-Ni alloy nanostructures might be transformed to Pt₃Ni phase via Ni removal through chemical etching. Besides the composition, the shape of the Pt-Ni alloy nanostructure also impacts the ORR activity because the latter highly depends on the exposed crystal facet.

Nowadays a lot of research groups over the world are reporting the synthesis of nano-size Pt-Ni particles, usually these publications are focus in batch-based generation of them, in which one of the most important restriction is the limitation of the product mass generated (typically few milligrams). Also another common problem use to be low reproducibility between samples. Bearing in mind the importance of these materials for the industry in the close future, we decided to create a protocol to synthesize PtNi₃ octahedral nanoparticles via flow-chemistry reaction.