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Download fileRevealing Surface Restraint-Induced Hexagonal Pd Nanocrystals via In Situ Transmission Electron Microscopy
journal contribution
posted on 2022-05-18, 21:07 authored by Ruiyang You, Zhemin Wu, Jian Yu, Fei Wang, Shiyuan Chen, Zhong-kang Han, Wentao Yuan, Hangsheng Yang, Yong WangAchieving
metal nanocrystals with metastable phase draws much attention
due to their anticipated fascinating properties, wheras it is still
challenging because their polymorphism nature and phase transition
mechanism remain elusive. Here, phase stability of face-centered cubic
(fcc) Pd nanocrystals was studied via in situ spherical
aberration (Cs)-corrected transmission electron microscopy (TEM).
By constructing a well-defined Pd/C composite structure, Pd nanocrystals
encapsulated by graphite, the dispersion process of fcc Pd was observed
through a nucleation and growth process. Interestingly, Cs-corrected
scanning TEM analysis demonstrated that the newly formed Pd nanocrystals
could adopt a metastable hexagonal phase, which was considered challenging
to obtain. Accordingly, formation mechanism of the hexagonal Pd nanocrystals
was proposed, which involved the combined effect of two factors: (1)
templating of graphite and (2) size effect. This work is expected
to offer new insight into the polymorphism of Pd nanocrystals and
pave the way for the future design of metastable metal nanomaterials.
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revealing surface restraintoffer new insightmetastable metal nanomaterialsc composite structureanticipated fascinating propertiesmetastable hexagonal phasepd nanocrystals encapsulatedhexagonal pd nanocrystalspd nanocrystalsphase stabilitydefined pdtwo factorstem ).studied viastill challengingspherical aberrationsize effectsitu growth processfuture designformation mechanismdispersion processconsidered challengingcombined effectcentered cubic