Designing plasmonic hollowc olloids with small interior nanogaps would allows tructural properties to be exploited that are normally linked to an ensemble of particles but within as ingle nanoparticle.N ow,asynthetic approach for constructing an ew class of frame nanostructures is presented. Fine control over the galvanic replacement reaction of Ag nanoprisms with Au precursors gave unprecedented Au particle-in-a-frame nanostructures with well-defined sub-2 nm interior nanogaps.T he prepared nanostructures exhibited superior performance in applications,such as plasmonic sensing and surface-enhanced Raman scattering, over their solid nanostructure and nanoframe counterparts.T his highlights the benefit of their interior hot spots,w hichc an highly promote and maximizet he electric field confinement within as ingle nanostructure.
A high-performance solar energy conversion platform was constructed by the intimate coupling of two different complementary semiconductors and morphology-controlled plasmonic metal nanocrystals in a controlled manner.
Devising colloidal nanoparticle assemblies with finely tunedtopological parameters is critical to the development of efficient and reliable plasmonic platformst hat can enable promising applications,s uch as surface-enhanced Raman scattering (SERS). Here, we report af acile synthesis strategy for the preparation of stable colloidal clusters of Au nanoparticles (Au NPCs) with well-controlled structuralp arameters, including the averagen umber and size of constituent nanoparticlesa nd the size of interparticle gaps, in which the galvanic replacement of Ag nanoprisms with controlled amount of Au precursors yielded Au NPCs with maneuvered particle sizes, while the other structural factorsw ere intact.The present approach could allow the precise exploration of the influence of particle size on the SERS activity of nanoparticle assemblies. Notably,t he prepared Au NPCs showed different particle-size dependency of their SERS activity along with the change in analyte concentration.F inite difference time domain simulation studies revealed that the experimental results can be correlated with the relative contributions of the magnitude of near-field enhancementa nd areal density of hot spots in the Au NPCs, which are determined by the size of constituent nanoparticles. This study therefore provides key designg uidelines to optimize the plasmonic functionofnanostructure assemblies.
Developing sensitive and stable hydrogen sensors is of great importance for sustainable energy development. Here, a novel hydrogen sensing platform is described based on colloidal clusters of Au@Pd core–shell nanoparticles (Au@Pd NPCs) with characteristic localized surface plasmon resonance (LSPR) properties. Au@Pd NPCs with well‐controlled topologies exhibit highly pronounced sensitivity for LSPR‐based hydrogen sensing in aqueous solution in comparison to their nanoparticle counterparts and previously reported Au–Pd bimetallic nanostructures, which can be attributed to highly promoted plasmonic field resulting from the cluster formation. Furthermore, Au@Pd NPCs show stable sensing capability for repeated hydrogen sensing cycles. The present strategy for devising high‐performance LSPR‐based hydrogen sensors via the controlled assembly of bimetallic nanoparticles can be applied to the development of efficient plasmonic platforms for various sensing applications.
The existence of various surface active sites within a nanocrystal (NC) catalyst complicates understanding their respective catalytic properties and designing an optimal catalyst structure for a desired catalytic reaction. Here, we developed a novel approach that allows unequivocal investigation on the intrinsic catalytic reactivity of the edge and terrace atoms of NCs. Through the comparison of the catalytic behaviors of edge‐covered Pd NCs, which were prepared by the selective deposition of catalytically inactive Au atoms onto the edge sites of rhombic dodecahedral (RD) Pd NCs, with those of the pristine RD Pd NCs toward alkyne hydrogenation and Suzuki–Miyaura coupling reactions, we could decouple the activity of the edge and {110}‐plane atoms of the Pd NCs without uncertainties. We expect that this study will provide an opportunity to scrutinize the surface properties of various NC catalysts to a more precise level and devise ideal catalysts for intended catalytic reactions.
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