Integrated Optimization of Crystal Facets and Nanoscale Spatial Confinement toward the Boosted Catalytic Performance of Pd Nanocrystals

Abstract

Tuning the surface chemical property and the local environment of nanocrystals is crucial for realizing a high catalytic performance in various reactions. Herein, we aim to elucidate the structure sensitivity of Pd facets on the surface catalytic hydrogenation reaction and to identify what role the nanoconfinement effect plays in the catalytic properties of Pd nanocrystal catalysts. By controlling the coating structures of mesoporous silica (mSiO 2 ) on Pd nanocrystals with different exposed facets that include {100}, {111}, and {hk0}, we present a series of Pd@mSiO 2 nanoreactors in core−shell and yolk−shell structures and the discovery of a partial-coated structure, which can provide different types of nanoconfinement, and we propose a seed size-dominated growth mechanism. We demonstrate that a superior activity was exhibited in Pd nanocrystals enclosed by the {hk0} facet as compared to the Pd{100} and Pd{111} facets, and substantially enhanced efficiency and stability were achieved in Pd@mSiO 2 particles with yolk−shell structures, indicating a crucial superiority of optimizing the configuration of crystal facets and nanoconfinement. Our study provides an efficient strategy to rationally design and optimize nanocatalysts for promoting catalytic performance.

Unexpectedly high thermal stability of Au nanotriangle@mSiO2 yolk–shell nanoparticles

“…Recent investigations on hetero-catalytic reactions indicated that the presence of metal catalysts in a yolk–shell coating structure could significantly enhance their catalytic performance. 30–36 However, not much is known about the thermal stability of yolk–shell structures although the different geometry likely alters the thermal stability and reshaping mechanism.…”

Wet-Chemical Synthesis of Concave Hexoctahedral Pd and Pd@Pt Nanocrystals for Methanol Electrooxidation

“…In recent decades, the synthesis of high-index-faceted nanocrystals (NCs) has paid intense attention to their excellent electrocatalytic performances to generate sustainable fuels. − For example, tetrahexahedral Pt nanocrystals exposed with 24 high-index {730} facets showed a 330% enhanced current density toward ethanol electrooxidation . The specific activity of concave Pd trisoctahedra exposed with {441} facets was 3.1-fold higher than that of Pd octahedra toward formic acid electrooxidation .…”