title: Anisotropic phase segregation and migration of Pt in nanocrystals en route to nanoframe catalysts.
abstract: Compositional heterogeneity in shaped, bimetallic nanocrystals offers additional variables to manoeuvre the functionality of the nanocrystal. However, understanding how to manipulate anisotropic elemental distributions in a nanocrystal is a great challenge in reaching higher tiers of nanocatalyst design. Here, we present the evolutionary trajectory of phase segregation in Pt-Ni rhombic dodecahedra. The anisotropic growth of a Pt-rich phase along the 〈111〉 and 〈200〉 directions at the initial growth stage results in Pt segregation to the 14 axes of a rhombic dodecahedron, forming a highly branched, Pt-rich tetradecapod structure embedded in a Ni-rich shell. With longer growth time, the Pt-rich phase selectively migrates outwards through the 14 axes to the 24 edges such that the rhombic dodecahedron becomes a Pt-rich frame enclosing a Ni-rich interior phase. The revealed anisotropic phase segregation and migration mechanism offers a radically different approach to fabrication of nanocatalysts with desired compositional distributions and performance.
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Niu
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: Nigel
authors.identifier: 0000-0001-7857-6841
authors.initials: N
authors.lastname: Becknell
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
authors.forename: Dohyung
authors.initials: D
authors.lastname: Kim
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.|Department of Chemistry, Tsinghua University, Beijing 100084, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: Nikolay
authors.initials: N
authors.lastname: Kornienko
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Kavli Energy NanoSciences Institute, Berkeley, California 94720, USA.
authors.forename: Gabor A
authors.initials: GA
authors.lastname: Somorjai
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.|Kavli Energy NanoSciences Institute, Berkeley, California 94720, USA.
authors.forename: Peidong
authors.initials: P
authors.lastname: Yang