Front Matter

Anderson, James A.; García, Marcos Fernández

doi:10.1142/9781860947476_fmatter

Cited by 12 publications

(17 citation statements)

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“…In a simple summary, the numerous investigations of metal cluster reactivity toward polar molecules have helped the understanding of the nature of chemical bonds that may be broken in this manner and also helped to identify what surfaces and clusters may possess the well-patterned Lewis acid/base sites optimal to promote this type of reactivity . This is particularly interesting in the development of alternative reactants and clusters (/metal surfaces) that would further the CAS mechanism for species with large bond energies, be they metal oxides, bimetallic interfaces, designed defect sites and step edges, or cluster-assembled materials. ,− …”

Section: Reactivity Of Metal Clusters With Polar Moleculesmentioning

confidence: 99%

Reactivity of Metal Clusters

2016

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We summarize here the research advances on the reactivity of metal clusters. After a simple introduction of apparatuses used for gas-phase cluster reactions, we focus on the reactivity of metal clusters with various polar and nonpolar molecules in the gas phase and illustrate how elementary reactions of metal clusters proceed one-step at a time under a combination of geometric and electronic reorganization. The topics discussed in this study include chemical adsorption, addition reaction, cleavage of chemical bonds, etching effect, spin effect, the harpoon mechanism, and the complementary active sites (CAS) mechanism, among others. Insights into the reactivity of metal clusters not only facilitate a better understanding of the fundamentals in condensed-phase chemistry but also provide a way to dissect the stability and reactivity of monolayer-protected clusters synthesized via wet chemistry.

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Section: Reactivity Of Metal Clusters With Polar Moleculesmentioning

confidence: 99%

Reactivity of Metal Clusters

2016

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“…Most industrial catalytic processes involve heterogeneous environments, often a solid foreign material and reactants in the gas and/or liquid phase. Transition metals, metal oxide based materials, and zeolites are among the most widely used materials in catalysis, although transition-metal sulfides, nitrides, carbides, phosphates, and phosphides, ion-exchange resins, and clays are also employed in some particular applications. , The physical, chemical, and catalytic properties of many such catalysts have been described in textbooks, monographies, , and specialized reviews. , …”

Section: Introductionmentioning

confidence: 99%

MXenes: New Horizons in Catalysis

2020

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Two-dimensional transition-metal carbides and nitrides, known as MXenes, have garnered increasing attention for nearly a decade by virtue of their versatile composition and structure, stability under certain conditions of interest in (electro)catalysis, and numerous appealing properties. Given the abundance of their components, large surface area and high laboratory-scale activities, MXenes are promising catalysts and supports for several heterogeneous catalytic and electrocatalytic reactions. This Perspective briefly summarizes the most relevant (electro)catalytic processes where MXenes hold promise as competitive alternatives to traditional Pt-group catalysts. We discuss how the interplay of metal elements with carbon, nitrogen, and various surface terminations modulates the catalytic activity of MXenes. In particular, we analyze the connection between experimental and simulated MXene structures and discuss the differences with bulk carbide extended surfaces. The great advances in synthesis routes and upscaling, in combination with realistic computational models, may give MXenes a leading role in the current quest for efficient catalytic processes.

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“…17−20 In conventional syntheses of supported metal nanoparticles, a metal precursor is deposited on an appropriate support via an impregnation methodology and then reduced, typically at elevated temperature with H 2 . 21 The reduction of dispersed metal species induces the formation of nanoparticles; however, these conditions must be carefully controlled since small nanoparticles are thermodynamically unstable and evolve toward the thermodynamic minimum of the bulk metal at elevated temperatures. 22−24 The tendency of nanoparticles to sinter therefore challenges the direct preparation of small, sizecontrolled nanoparticles on high-surface area supports.…”

Section: ■ Introductionmentioning

confidence: 99%

Synthesis of Supported Pd⁰ Nanoparticles from a Single-Site Pd²⁺ Surface Complex by Alkene Reduction

Mouat¹,

Whitford²,

Chen³

et al. 2018

Chem. Mater.

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A surface metal-organic complex, (-AlOx)Pd(acac) (acac = acetylacetonate), is prepared by chemically grafting the precursor Pd(acac)(2) onto gamma-Al2O3 in toluene at 25 degrees C. The resulting surface complex is characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and dynamic nuclear polarization surface-enhanced solid-state nuclear magnetic resonance spectroscopy (DNP SENS). This surface complex is a precursor in the direct synthesis of size-controlled Pd nanoparticles under mild reductive conditions and in the absence of additional stabilizers or pretreatments. Indeed, upon exposure to gaseous ethylene or liquid 1-octene at 25 degrees C, the Pd2+ species is reduced to form Pd-0 nanoparticles with a mean diameter of 4.3 +/-0.6 nm, as determined by scanning transmission electron microscopy (STEM). These nanoparticles are catalytically relevant using the aerobic 1-phenylethanol oxidation as a probe reaction, with rates comparable to a conventional Pd/Al2O3 catalyst but without an induction period. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and temperature-programmed reaction mass spectrometry (TPR-MS) reveal that the surface complex reduction with ethylene coproduces H-2, acetylene, and 1,3-butadiene. This process reasonably proceeds via an olefin activation/coordination/insertion pathway, followed by betahydride elimination to generate free Pd-0. The well-defined nature of the single-site supported Pd2+ precursor provides direct mechanistic insights into this unusual and likely general reductive process.

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Front Matter

Cited by 12 publications

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Reactivity of Metal Clusters

Reactivity of Metal Clusters

MXenes: New Horizons in Catalysis

Synthesis of Supported Pd⁰ Nanoparticles from a Single-Site Pd²⁺ Surface Complex by Alkene Reduction

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Front Matter

Cited by 12 publications

References 0 publications

Reactivity of Metal Clusters

Reactivity of Metal Clusters

MXenes: New Horizons in Catalysis

Synthesis of Supported Pd0 Nanoparticles from a Single-Site Pd2+ Surface Complex by Alkene Reduction

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Synthesis of Supported Pd⁰ Nanoparticles from a Single-Site Pd²⁺ Surface Complex by Alkene Reduction