Highly Branched Concave Au/Pd Bimetallic Nanocrystals with Superior Electrocatalytic Activity and Highly Efficient SERS Enhancement

Zhang, Linfei; Zhong, Shengliang; Xu, An‐Wu

doi:10.1002/anie.201205279

Cited by 156 publications

(112 citation statements)

References 70 publications

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“…37 High resolution transmission electron microscopy (HR-TEM) measurements of the HAuNFs (synthesized with 150 mM AA) showed that the spikes had edges and corners (Fig. 3A, ESI: S9A and S10A †), and they exhibit zig-zag features on the borders, demonstrating the presence of low-coordinate 41 In addition, it can be seen from Fig. 3D-F that, a high density of dislocations, steps and kinks are exposed on the HAuNF spikes, which have been reported to be the basis of high catalytic activity in gold catalysts.…”

Section: Structural and Optical Properties Of Haunfsmentioning

confidence: 98%

One-step fabrication of hollow-channel gold nanoflowers with excellent catalytic performance and large single-particle SERS activity

Benz

Wheeler

et al. 2016

Nanoscale

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Hollow metallic nanostructures have shown potential in various applications including catalysis, drug delivery and phototherapy, owing to their large surface areas, reduced net density, and unique optical properties. In this study, novel hollow gold nanoflowers (HAuNFs) consisting of an open hollow channel in the center and multiple branches/tips on the outer surface are fabricated for the first time, via a facile one-step synthesis using an auto-degradable nanofiber as a bifunctional template. The one-dimensional (1D) nanofiber acts as both a threading template as well as a promoter of the anisotropic growth of the gold crystal, the combination of which leads to the formation of HAuNFs with a hollow channel and nanospikes. The synergy of favorable structural/surface features, including sharp edges, open cavity and high-index facets, provides our HAuNFs with excellent catalytic performance (activity and cycling stability) coupled with large single-particle SERS activity (including ∼30 times of activity in ethanol electro-oxidation and ∼40 times of single-particle SERS intensity, benchmarked against similar-sized solid gold nanospheres with smooth surfaces, as well as retaining 86.7% of the initial catalytic activity after 500 cycles in ethanol electro-oxidation). This innovative synthesis gives a nanostructure of the geometry distinct from the template and is extendable to fabricating other systems for example, hollow-channel silver nanoflowers (HAgNFs). It thus provides an insight into the design of hollow nanostructures via template methods, and offers a versatile synthetic strategy for diverse metal nanomaterials suited for a broad range of applications.

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Section: Structural and Optical Properties Of Haunfsmentioning

confidence: 98%

One-step fabrication of hollow-channel gold nanoflowers with excellent catalytic performance and large single-particle SERS activity

Benz

Wheeler

et al. 2016

Nanoscale

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“…In order to evaluate the SERS sensitivity of the OMASC-28, the SERS response was examined by using crystal violet (CV) dye as the probe molecule, which has also been widely used in previous experiments [ 17 ] and our recent studies. [ 18 ] To precisely …”

Section: Full Paper Full Paper Full Papermentioning

confidence: 99%

Plasmonic Silver Supercrystals with Ultrasmall Nanogaps for Ultrasensitive SERS‐Based Molecule Detection

Tian

Deng

Zhao

et al. 2015

Advanced Optical Materials

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surface plasmon resonance. The plasmonic coupling effect at the nanometer gaps between metallic nanoparticles, i.e., the plasmonic hot spots, has also been utilized to further increase the SERS signals. [ 3 ] Extensive studies have been focused on creating hot spots spaced by small dielectric gaps of less than 10 nm. In addition to the original SERS platform made from electrochemically roughened surface, [ 4 ] a diverse novel SERS substrates have been developed, which include the well-ordered patterned arrays fabricated via lithographic techniques. [ 5 ] However, these techniques are limited by their low throughput, expensive operating cost, and small SERS active area. Importantly, it is still diffi cult to process small nanogaps down to sub-5 nm over large area. As such, size/shape controlled colloidal nanoparticles and their assemblies such as dimers, trimers, liner chains, core-satellite structures are attractive options due to the ability to synthesize through wet chemical approaches in bulk scale without the need of expensive instrumentation. [ 6 ] However, owing to the "coffee ring" effect, regulating the geometrical dimension, i.e., uniform nanoparticle gaps between colloidal nanoparticles via spontaneous aggregation or assembly are challenging. [ 7 ] With the assistance of surface ligands, nanoparticles can be assembled into superlattices, [ 8 ] but the introduction of polymer ligands unavoidably sacrifi ces the sensitivity of signals in a variety of applications, such as SERS, biosensors, plasmon-enhanced fl uorescence. Therefore, the central problem is to homogeneously produce well-defi ned plasmonic structures that can reproducibly fabricate sub-5 nm nanogaps with controllable gap distance and enhanced hot spot density within the plasmonic structure.In comparison with the nanoparticle superlattices obtained via self-assembly of metallic nanocrystals by means of the polymer ligands, [ 8 ] the ordered nanoparticle supercrystals may also be synthesized via replicating 3D colloidal (e.g., polymer or SiO 2 spheres) template [ 9 ] or ordered mesoporous silica (e.g., KIT-6, SBA-15, MCM-48) templates. [ 10 ] For example, 2D dimpled gold nanoplates were fabricated by vapor reduction using a 3D lattice of silica nanospheres (≈40 nm) as a template. [ 9 ] Unfortunately, the dimpled-type array is not suitable for the applications in SERS. Using ordered mesoporous silica (KIT-6 and SBA-15) template, Yamauchi's group has successfully fabricated polyhedral mesoporous Pt nanoparticles through a chemical reduction route. [ 10 ] However, the synthesis of highly Metallic periodic structures provide unique optical and photonic coupling effects. However, geometrically precise control of periodic structure is particularly challenging when studying scale at few nanometer. Here, a new class of highly ordered silver plasmonic supercrystals is successfully synthesized by means of a nanocasting process using ordered mesoporous silica as template. During the nanocasting via a chemical reduction, the diffusibility, viscosit...

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“…The resulting 3D nanostructures are generally characterized by rough surfaces, high porosity, high densities of crystalline defects, and complex morphologies, with cooperative effects between the building blocks [24][25][26][27][28][29][30]. For example, a porous Pd catalyst showing high catalytic activity in the Suzuki coupling reaction has been reported, and the high activity was attributed to the high concentration of low-coordinate surface atoms [27].…”

Section: Introductionmentioning

confidence: 97%

Fabrication of a PdAg mesocrystal catalyst for the partial hydrogenation of acetylene

Liu

Yang

et al. 2015

Journal of Catalysis

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Highly Branched Concave Au/Pd Bimetallic Nanocrystals with Superior Electrocatalytic Activity and Highly Efficient SERS Enhancement

Cited by 156 publications

References 70 publications

One-step fabrication of hollow-channel gold nanoflowers with excellent catalytic performance and large single-particle SERS activity

One-step fabrication of hollow-channel gold nanoflowers with excellent catalytic performance and large single-particle SERS activity

Plasmonic Silver Supercrystals with Ultrasmall Nanogaps for Ultrasensitive SERS‐Based Molecule Detection

Fabrication of a PdAg mesocrystal catalyst for the partial hydrogenation of acetylene

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