Skeletal octahedral nanoframe with Cartesian coordinates via geometrically precise nanoscale phase segregation in a Pt@Ni core-shell nanocrystal.
Catalytic properties of nanoparticles can be significantly enhanced by controlling nanoscale alloying and its structure. In this work, by using a facet-controlled Pt@Ni core-shell octahedron nanoparticle, we show that the nanoscale phase segregation can have directionality and be geometrically controlled to produce a Ni octahedron that is penetrated by Pt atoms along three orthogonal Cartesian axes and is coated by Pt atoms along its edges. This peculiar anisotropic diffusion of Pt core atoms along the ⟨100⟩ vertex, and then toward the ⟨110⟩ edges, is explained via the minimum strain energy for Ni-Ni pair interactions. The selective removal of the Ni-rich phase by etching then results in structurally fortified Pt-rich skeletal PtNi alloy framework nanostructures. Electrochemical evaluation of this hollow nanoframe suggests that the oxygen reduction reaction (ORR) activity is greatly improved compared to conventional Pt catalysts.
Aram
A
Oh
§Korea Basic Science Institute (KBSI), Seoul 136-713, Republic of Korea.
Hionsuck
H
Baik
⊥Graduate School of Energy Environment Water and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea.
Dong Shin
DS
Choi
Jae Yeong
JY
Cheon
Byeongyoon
B
Kim
⊥Graduate School of Energy Environment Water and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea.
Heejin
H
Kim
#Department of Chemistry, Konkuk University, Seoul 143-701, Republic of Korea.
Seong Jung
SJ
Kwon
Sang Hoon
SH
Joo
⊥Graduate School of Energy Environment Water and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea.
Yousung
Y
Jung
Kwangyeol
K
Lee
alloy; crystal growth; nanoparticles; phase segregation; platinum