Pt Diffusion Dynamics for the Formation Cr–PtCore–Shell Nanoparticles.

Layeredcore–shell bimetallic Cr–Pt nanoparticleswere prepared by the formation and later reduction of an intermediatePt-ion-containing supramolecular complex onto preformed Cr nanoparticles.The resultant nanoparticles were characterized by X-ray diffractionanalysis, transmission electron microscopy, X-ray photoelectron spectroscopy,and aberration-corrected scanning transmission electron microscopy.The results are consistent with the presence of Pt diffusion duringor after bimetallic nanoparticle formation, which has resulted ina Pt/Cr-alloyed core and shell. We postulate that such Pt diffusionoccurs by an electric-field-assisted process according to Cabrera–Motttheory and that it originates from the low work function of the preformedoxygen-defective Cr nanoparticles and the rather large electron affinityof Pt. [ABSTRACT FROM AUTHOR]