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Anisotropic phase segregation and migration of Pt in nanocrystals en route to nanoframe catalysts
Control of nanoscopic segregation of the elements in Pt-Ni rhombic dodecahedra (RD) was discovered to create a 3-D Pt3Ni nanoframe.
Significance and Impact
Being able to control the element spatial distribution within nanocrystals is an advanced strategy for obtaining catalysts with new morphologies and structure.
- Initial Pt-rich alloy grows in <111> and <200> directions, providing compositional anisotropy
- Pt segregates to axes of RD such that when Ni-rich phase is corroded, tetradecapod (14 arm) structure is obtained
- Pt migrates to edges of RD after certain time such that when Ni-rich phase is corroded, nanoframe can be obtained
Niu, Z.; Becknell, N.; Yu, Y.; Kim, D.; Chen, C.; Kornienko, N.; Somorjai, G. A.; Yang, P. Nat. Mater. (2016) DOI: 10.1038/NMAT4724