Atomic Crystal Facet Engineering of Core-Shell Nanotetrahedrons Restricted under Sub-10 Nanometer Region.
basic_science · Level V
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- Record sourced from PubMed, PMID 33588529.
- Also identified by DOI 10.1021/acsnano.0c10376.
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Abstract
Simultaneously engineering the size and surface crystal facets of bimetallic core-shell nanocrystals offers an effective route to not only reduce the extravagance of innermost core metal and maximize the utilization efficiency of shell atoms but also strengthen the core-to-shell interaction <i>via</i> ligand and/or strain effects. Herein, we systematically study the architecture transition and crystal facet engineering at the atomic level on the surface of sub-5 nm Pd(111) tetrahedrons (Ths), aimed at embodying how the variations in the local facet and shape of a sub-10 nm core-shell structure affect its surface geometrical properties and electronic structures. Specifically, surface atomic replication is predominant when the shell metal deposits less than five atomic layers, thus forming a series of Pd@M (M = Pt, Ru, and Rh) core-shell Ths enclosed by (111) facets (∼6.8 nm), while over five atomic layers, spontaneous facets tropism of each metal is predominant, where Pt atoms still follow <i>fcc</i>-(111) packing, Ru atoms select <i>hcp</i>-phase stacking, and Rh atoms choose <i>fcc</i>-(100) crystallization, respectively. In particular, Pt atoms take a seamless geometrical transformation from Pd@Pt Ths into Pd@Pt truncated octahedrons (TOhs, ∼7.6 nm). As a proof-of-concept application, such sub-10 nm core-shell architectures with Pt skin show a component-dependent relationship toward oxygen reduction reaction (ORR), where the catalytic activity follows the order of Pd@Pt(111) TOhs (<i>E</i><sub>1/2</sub> = 0.916 V, 1.632 A mg<sub>Pt</sub><sup>-1</sup>) > Pd@Pt(111) Ths > Pt black. Meanwhile the Ru skin show a facet-dependent relationship toward acidic hydrogen evolution reaction (HER) where the catalytic activity follows the order of Pd@Ru(111) Ths > Pd@Ru(<i>hcp</i>) Ths > Pd Ths.