Effects of the Nitridation of Y and USY Zeolites on their Catalytic Activity for the Base Catalyzed Knoevenagel Condensation

Srasra, Mondher; Delsarte, Stéphanie; Gaigneaux, Éric M.

doi:10.1007/s11244-009-9290-5

Cited by 18 publications

(7 citation statements)

References 36 publications

(37 reference statements)

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“…The Journal of Physical Chemistry C and what has been observed previously on H-terminated silicon surfaces. [12][13][14][15][16][17]61 Despite this fact, only 2/3 of the surface hydrogen is consumed on both surfaces at saturation exposure. This suggests that if one Cu(hfac) fragment reacts with a single surface functionality per silicon dimer (for example, NH 2 group), only two out of three hydrogen atoms of the initial NH 3 molecule are consumed in the reaction, leaving the remaining hydrogen atom on the surface to desorb at 800 K. This also means that the nitrogen atom from this functionality remains on the silicon surface and may be a factor in defining the interactions between the silicon and deposited copper.…”

Section: Resultsmentioning

confidence: 99%

Controlling the Formation of Metallic Nanoparticles on Functionalized Silicon Surfaces

2012

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With scaling down the size of the features in modern electronic devices, it becomes vital to control surface reactions at the interface for clean deposition on semiconductor substrates. Chemical functionalization of silicon surfaces provides a new approach for tuning the structure and properties of the interfaces formed with this semiconductor. The functionalized surfaces, such as H− Si(100), NH−Si(100), and NH 2 −Si(100) can be used to prevent surface oxidation at the silicon interface, and OH−Si(100) can be utilized to limit surface diffusion in a reaction with a metal−organic precursor. A model copper metal−organic precursor, copper (hexafluoroacetylacetonato)vinyltrimethylsilane or Cu(hfac)-VTMS, was used to grow copper nanostructures by chemical vapor deposition (CVD), as verified by atomic force microscopy (AFM), infrared spectroscopy (MIR-FTIR), X-ray photoelectron spectroscopy (XPS), and temperatureprogrammed desorption (TPD) supported with density functional theory calculations (DFT). These methods help to follow surface reaction products and kinetics of surface processes. The NH 2 −Si(100) surface yields the largest copper nanostructures at room temperature, and this surface is the most reactive in the CVD process. Understanding the molecular-level mechanisms of the copper deposition onto functionalized surfaces will help to control the nanostructure formation, their properties, and the interface with the solid substrate.

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Section: Resultsmentioning

confidence: 99%

Controlling the Formation of Metallic Nanoparticles on Functionalized Silicon Surfaces

2012

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“…An increase of the amount of these species brought a more pronounced amorphization. A fact which should be avoided since the structural changes undergone by the zeolites upon nitridation constitutes a crucial factor that can influence its catalytic performance. , …”

Section: Resultsmentioning

confidence: 99%

Nitrided Zeolites: A Spectroscopic Approach for the Identification and Quantification of Incorporated Nitrogen Species

Srasra¹,

Delsarte²,

Gaigneaux³

2010

J. Phys. Chem. C

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The combination of X-ray photoelectron spectroscopy (XPS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) allowed a clear identification and quantification of nitrogenous species incorporated upon nitridation in three different zeolites one Y zeolite (Si/Al ratio of 2.6) and two ultrastable Y zeolites (Si/Al ratios of 13 and 37). Both the amount and the chemical nature of incorporated nitrogen species were controlled by the nitridation temperature. Namely, an increase of the temperature induces an increase of the nitrogen content and the appearance of nitrogenous species in the following order of increasing temperature: NH4 +, adsorbed NH3, −NH2, >NH, and >N−. Based on these spectroscopic results, a mechanism of nitridation in function of temperature was proposed, this mechanism being independent of the properties of the parent zeolite. We evidenced here that the replacement of hydroxyls groups located in the microposity of the zeolite by nitrogen species was effective which can be very motivating result for the application of these materials as shape selective catalysts.

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“…In the last few years a number of papers have addressed the subject providing valuable information on the exact position of ammonium compounds and the mechanism of catalytic reaction. 249,250 Both theoretical and experimental studies have been performed to investigate the nitrogen substitution in zeolites. Agarwal et al applied density functional theory to reveal the mechanism of nitrogen substitution in FAU-and MFI-type materials.…”

Section: Hydrothermal Substitution Of Framework Cationsmentioning

confidence: 99%

Tailored crystalline microporous materials by post-synthesis modification

et al. 2013

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Crystalline microporous solids are an important class of inorganic materials with uses in different areas impacting our everyday lives, namely as catalysts, adsorbents, and ion exchangers. Advancements in synthesis have been invaluable in expanding the classical aluminosilicate zeolites to new unique framework types and compositions, motivating innovative developments. However, the inexhaustible post-synthetic options to tailor zeolite properties have been and will continue to be indispensable to realize emerging and to improve conventional applications. Starting from the routine drying and template removal processes that every zeolite must experience prior to use, a wide spectrum of treatments exists to alter individual or collective characteristics of these materials for optimal performance. This review documents the toolbox of post-synthetic strategies available to tune the properties of zeolitic materials for specific functions. The categorisation is based on the scale at which the alteration is aimed at, including the atomic structure (e.g. the introduction, dislodgment, or replacement of framework atoms), the micropore level (e.g. template removal and functionalisation by inorganic and organic species), and the crystal and particle levels (e.g. the introduction of auxiliary porosity). Through examples in the recent literature, it is shown that the combination of post-synthetic methods enables rational zeolite design, extending the characteristics of these materials way beyond those imposed by the synthesis conditions.

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Effects of the Nitridation of Y and USY Zeolites on their Catalytic Activity for the Base Catalyzed Knoevenagel Condensation

Cited by 18 publications

References 36 publications

Controlling the Formation of Metallic Nanoparticles on Functionalized Silicon Surfaces

Controlling the Formation of Metallic Nanoparticles on Functionalized Silicon Surfaces

Nitrided Zeolites: A Spectroscopic Approach for the Identification and Quantification of Incorporated Nitrogen Species

Tailored crystalline microporous materials by post-synthesis modification

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