Shaping non-noble metal nanocrystals <i>via</i> colloidal chemistry

Mantella, Valeria; Castilla-Amorós, Laia; Buonsanti, Raffaella

doi:10.1039/d0sc03663c

Cited by 20 publications

(27 citation statements)

References 101 publications

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“…Nevertheless, well-controlled synthesis is able to produce narrow size/shape distributions. [7,17,[215][216][217] In the following, the application of Ni and CuNi nanoparticles supported on zirconia (ZrO 2 ) for methane reforming is discussed, [259][260][261][262] with operando NAP-XPS studies revealing reaction-induced surface composition changes. H r ∆ = + − ).…”

Section: Bimetallic Cuni Nanoparticles Supported By Zro 2 : Ch X -Indmentioning

confidence: 99%

“…Previous work along these lines mostly focused on metal clusters with up to about 100 atoms, representing the so-called non-scalable regime, in which nearly every atom counts. Three major synthesis routes were followed: i) clusters prepared and mass-selected in the gas phase, prior to "soft-landing" on suitable supports, [29][30][31][211][212][213][214] ii) colloidal size-and shape-controlled nanoparticles impregnated on various supports, [7,24,[215][216][217] and iii) wet-chemically prepared ligand-protected clusters in solution, [218][219][220][221][222][223][224] "size-purified" by size-exclusion-chromatography (SEC) or gel-electrophoresis prior to deposition on a support. Although the initial state of such monodisperse nanoparticles is well-defined, they typically undergo structural rearrangements and/or atom mobility during catalysis, which is why operando characterization is once more inevitable to understand their catalytic performance.…”

Section: Atomically-precise Au 38 Clusters Supported By Ceo 2 : Intracluster Restructuring and Atom Mobility During Co Oxidationmentioning

confidence: 99%

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Operando Surface Spectroscopy and Microscopy during Catalytic Reactions: From Clusters via Nanoparticles to Meso‐Scale Aggregates

Rupprechter

2021

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described as metal dispersion (number of metal surface atoms relative to the total number of metal atoms in the catalyst), whereas the support is characterized by the specific surface area (m 2 g −1). For hemispherical metal particles of ≈1.5, 2, 5, and 10 nm diameter, the dispersion is about 0.8, 0.6, 0.3, and 0.1, respectively, illustrating why the nanoscale is required not to waste precious metal inside the particles. The ultimate dispersion is, of course, provided by single metal atoms and this concept is followed in "single atom catalysis" or "single site catalysis". [10-17] However, the adsorption and reaction steps of a catalytic reaction do typically not occur on isolated single atoms, but also involve neighboring sites, for example, of the oxide support [18] or of a metal matrix (for bimetallic nanoparticles, active metal atoms may be embedded in an inert or less-active metal matrix [11,19-23]). The so-called site isolation of active atoms may prevent CC bond cleavage (coking), which requires at least two neighboring active metals. In any case, the stability of the single atoms is the key challenge, as atoms may diffuse and sinter. Furthermore, for example, Pt, Pd, Cu, or Au atoms are mobilized by CO, [24-28] forming CO-M 1 units that may eventually sinter into larger clusters. Herein, we define metal clusters as entities with less than ≈100 atoms, characterizing the so-called "non-scalable" regime (Figure 1a). [29] Their atomic and electronic structure is significantly different from that of bulk metals, for example, with respect to atom positions (icosahedral vs face centered cubic fcc), distances (lattice contraction or expansion), and band structure (semiconductor vs metal). Clearly, these properties are size-dependent ("each atom counts" [30,31]), with pronounced impact on adsorption and reaction properties. [5,32] Accordingly, nanoparticles with more than ≈100 atoms are in the "scalableregime" and start to have or exhibit bulk atomic and electronic structure. [6,32-34] Nevertheless, the relative contributions of corner, edge, step, terrace and phase boundary sites on the surface of a nanoparticle (Figure 1b,c) are still size-dependent. [35,36] Meso-scale ("black") powders of metals are clearly bulk-like and have very low dispersion (Figure 1d), but the µm-sized aggregates still consist of adjoining nanocrystals with structured surfaces, comparable to that of true nanoparticles. Operando characterization of working catalysts, requiring per definitionem the simultaneous measurement of catalytic performance, is crucial to identify the relevant catalyst structure, composition and adsorbed species. Frequently applied operando techniques are discussed, including X-ray absorption spectroscopy, near ambient pressure X-ray photoelectron spectroscopy and infrared spectroscopy. In contrast to these area-averaging spectroscopies, operando surface microscopy by photoemission electron microscopy delivers spatially-resolved data, directly visualizing catalyst heterogeneity. For thorough interpretation, the exper...

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Section: Bimetallic Cuni Nanoparticles Supported By Zro 2 : Ch X -Indmentioning

confidence: 99%

Section: Atomically-precise Au 38 Clusters Supported By Ceo 2 : Intracluster Restructuring and Atom Mobility During Co Oxidationmentioning

confidence: 99%

Operando Surface Spectroscopy and Microscopy during Catalytic Reactions: From Clusters via Nanoparticles to Meso‐Scale Aggregates

Rupprechter

2021

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“…The growth of shaped-controlled nanoparticles critically depends on the applied synthesis conditions, and the reader is referred to reviews for in-depth accounts [55,68,69]. The size, shape, lattice structure and adsorption properties of the Pt and Pd NPs were evaluated by (HR-)TEM, aided by fast Fourier transform (FFT) analysis, XRD and CO-FTIR.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Shape-Controlled Pt and Pd Nanoparticles on Selective Catalytic Hydrodechlorination of Trichloroethylene

et al. 2020

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Tailoring the shape of nanoscale materials enables obtaining morphology-controlled surfaces exhibiting specific interactions with reactants during catalytic reactions. The specifics of nanoparticle surfaces control the catalytic performance, i.e., activity and selectivity. In this study, shape-controlled Platinum (Pt) and Palladium (Pd) nanoparticles with distinct morphology were produced, i.e., cubes and cuboctahedra for Pt and spheres and polyhedra/multiple-twins for Pd, with (100), (111 + 100), curved/stepped and (111) facets, respectively. These particles with well-tuned surfaces were subsequently deposited on a Zirconium oxide (ZrO2) support. The morphological characteristics of the particles were determined by high resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD), while their adsorption properties were investigated by Fourier transform infrared spectroscopy (FTIR) of CO adsorbed at room temperature. The effect of the nanoparticle shape and surface structure on the catalytic performance in hydrodechlorination (HDCl) of trichloroethylene (TCE) was examined. The results show that nanoparticles with different surface orientations can be employed to affect selectivity, with polyhedral and multiply-twinned Pd exhibiting the best ethylene selectivity.

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“…However, the efficiency and selectivity are still too low for industrial-scale implementation. [2,3] Hori and Takahashi et al have demonstrated that the Cu (100) facet facilitates the formation of ethylene while the Cu (111) facet favors methane generation. [4,5] This model catalyst study has inspired the exploration of colloidal Cu NCs with dominantly exposed (100) facets for enhancing CO 2 -to-C 2 H 4 selectivity.…”

Section: Introductionmentioning

confidence: 99%

Facet‐Selective Deposition of Ultrathin Al₂O₃ on Copper Nanocrystals for Highly Stable CO₂ Electroreduction to Ethylene

Lei

et al. 2021

Angewandte Chemie

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Catalysts based on Cu nanocrystals (NCs) for electrochemical CO 2 -to-C 2+ conversion with high activity have been a subject of considerable interest, but poor stability and low selectivity for a single C 2+ product remain obstacles for realizing sustainable carbon-neutral cycles. Here, we used the facet-selective atomic layer deposition (FS-ALD) technique to selectively cover the (111) surface of Cu NCs with ultrathin Al 2 O 3 to increase the exposed facet ratio of (100)/(111), resulting in a faradaic efficiency ratio of C 2 H 4 /CH 4 for overcoated Cu NCs 22 times higher than that for pure Cu NCs. Peak performance of the overcoated catalyst (Cu NCs/ Al 2 O 3 -10C) reaches a C 2 H 4 faradaic efficiency of 60.4 % at a current density of 300 mA cm À2 in 5 M KOH electrolyte, when using a gas diffusion electrode flow cell. Moreover, the Al 2 O 3 overcoating effectively suppresses the dynamic mobility and the aggregation of Cu NCs, which explains the negligible activity loss and selectivity degradations of Cu NCs/Al 2 O 3 -10C shown in stability tests.

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Shaping non-noble metal nanocrystals via colloidal chemistry

Abstract: Non-noble metal nanocrystals with well-defined shapes have been attracting increasingly more attention in the last decade as potential alternatives to noble metals, by virtue of their Earth abundance combined with...

Cited by 20 publications

References 101 publications

Operando Surface Spectroscopy and Microscopy during Catalytic Reactions: From Clusters via Nanoparticles to Meso‐Scale Aggregates

Operando Surface Spectroscopy and Microscopy during Catalytic Reactions: From Clusters via Nanoparticles to Meso‐Scale Aggregates

The Effect of Shape-Controlled Pt and Pd Nanoparticles on Selective Catalytic Hydrodechlorination of Trichloroethylene

Facet‐Selective Deposition of Ultrathin Al₂O₃ on Copper Nanocrystals for Highly Stable CO₂ Electroreduction to Ethylene

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Shaping non-noble metal nanocrystals via colloidal chemistry

Abstract: Non-noble metal nanocrystals with well-defined shapes have been attracting increasingly more attention in the last decade as potential alternatives to noble metals, by virtue of their Earth abundance combined with...

Cited by 20 publications

References 101 publications

Operando Surface Spectroscopy and Microscopy during Catalytic Reactions: From Clusters via Nanoparticles to Meso‐Scale Aggregates

Operando Surface Spectroscopy and Microscopy during Catalytic Reactions: From Clusters via Nanoparticles to Meso‐Scale Aggregates

The Effect of Shape-Controlled Pt and Pd Nanoparticles on Selective Catalytic Hydrodechlorination of Trichloroethylene

Facet‐Selective Deposition of Ultrathin Al2O3 on Copper Nanocrystals for Highly Stable CO2 Electroreduction to Ethylene

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Facet‐Selective Deposition of Ultrathin Al₂O₃ on Copper Nanocrystals for Highly Stable CO₂ Electroreduction to Ethylene