Ethylene Hydrogenation over Platinum Nanoparticle Array Model Catalysts Fabricated by Electron Beam Lithography:  Determination of Active Metal Surface Area

Grunes, Jeff; Zhu, Julie; Anderson, Erik; Somorjai, Gábor A.

doi:10.1021/jp021641e

Cited by 140 publications

(136 citation statements)

References 21 publications

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“…Ordered two-dimensional arrays of monometallic or metal/oxide bifunctional nanocrystals have been prepared as model catalysts via electron lithography 13 and drop-casting 14 respectively, but afford extremely low surface areas with co-located active sites. Hence, there are no synthetic routes able to control either the nanoscale spatial distribution, or the communication between, individual functions within three-dimensional porous solids.…”

mentioning

confidence: 99%

Spatially orthogonal chemical functionalization of a hierarchical pore network for catalytic cascade reactions

et al. 2015

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. (2016) 'Spatially orthogonal chemical functionalization of a hierarchical pore network for catalytic cascade reactions.', Nature materials., 15 (2). pp. 178-182.Further information on publisher's website:Publisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

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confidence: 99%

Spatially orthogonal chemical functionalization of a hierarchical pore network for catalytic cascade reactions

et al. 2015

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“…This field developed rapidly by use of model catalysts, first single-crystal surfaces (7)(8)(9)(10)(11)(12), then monodispersed nanoclusters deposited on oxide surfaces by lithography techniques (13)(14)(15)(16)(17) (Fig. 1).…”

mentioning

confidence: 99%

Clusters, surfaces, and catalysis

Somorjai¹,

Contreras

Montano

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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245

187

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The surface science of heterogeneous metal catalysis uses model systems ranging from single crystals to monodispersed nanoparticles in the 1-10 nm range. Molecular studies reveal that bond activation (C-H, H-H, C-C, CAO) occurs at 300 K or below as the active metal sites simultaneously restructure. The strongly adsorbed molecules must be mobile to free up these sites for continued turnover of reaction. Oxide-metal interfaces are also active for catalytic turnover. Examples using C-H and CAO activation are described to demonstrate these properties. Future directions include synthesis, characterization, and reaction studies with 2D and 3D monodispersed metal nanoclusters to obtain 100% selectivity in multipath reactions. Investigations of the unique structural, dynamic, and electronic properties of nanoparticles are likely to have major impact in surface technologies. The fields of heterogeneous, enzyme, and homogeneous catalysis are likely to merge for the benefit of all three.catalytic bond activation ͉ high selectivity catalyst design ͉ molecular ingredients of catalysis M etal containing catalysts are clusters of 1-10 nm in size. These are grouped into three types: heterogeneous catalysts that are embedded in high surface area supports, usually oxides, to optimize their surface area and thus the number of molecules they produce per second and also to optimize their thermal and chemical stability. They are used mostly at high temperatures (400-800 K) and in the presence of vapor phase reactants and product molecules. Enzyme catalysts operate in solution, mostly in water near 300 K, and the metal-containing active sites are surrounded by proteins that maintain structural mobility (1). Homogeneous catalysts function in the same solution in which the reactant and product molecules are dissolved, mostly in organic solvents, and used in the 300-500 K temperature range. Because of the different operating conditions and for reasons of history, the three fields of catalysis developed independently and became separate fields of science within different subdisciplines of chemistry. Heterogeneous catalysis was practiced mostly by physical chemists and chemical engineers, enzyme catalysis by biochemists, and homogeneous catalysis by inorganic and organometallic chemists.Catalytic reactions are distinguished from stoichiometric reactions by having many turnovers per reacting active site producing 10 2 to 10 6 molecules per site. Some of these catalytic reactions are very fast. For instance, the catalytic oxidation of carbon monoxide (CO) produces thousands of CO 2 molecules per metal surface site per second above ignition where the exothermicity of the process makes it self-sustaining in temperature and the reaction rate is only limited by the speed of transport of molecules to and from the catalyst surface (2-4). Ethylene hydrogenation, another exothermic reaction, turns over to produce ethane Ϸ10 times per metal surface site per second at 300 K on Pt(111) (5). The catalytic conversion of n-hexane to benzene or to branched...

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“…Small Pt particles as well as large Pt particles showed catalytic activity in deuteration of ethene with turnover rates comparable to literature values. 53 The small particles exhibited a deactivation period in the first 10 min of reaction that was not related to particle sintering or particle shape changes, but most likely to changes in the morphology of the particles. 47 The decrease in the white line intensity with increasing temperature during the reaction on small particles reflects an increase in the electron density of the particles.…”

Section: Resultsmentioning

confidence: 93%

“…A stable ethene conversion of 0.12% and 0.08% was determined for small and large Pt particles, respectively, in good accord with the results obtained on B15 nm sized Pt particles tested under similar conditions. 53 The Pt-metal loading-based ethane turnover rates were 22 The GISAXS study during the deuterium-ethene reaction showed that small Pt particles on n-GaN changed their shape reversibly, while large particles were not affected. The decreased lateral diameter of small particles in reactant gas atmosphere is attributed to rearrangements of particle facets.…”

Section: Hydrogenation Of Ethene With Deuteriummentioning

confidence: 99%

Combined TPRx, in situ GISAXS and GIXAS studies of model semiconductor-supported platinum catalysts in the hydrogenation of ethene

Wyrzgol

Schäfer

Lee

et al. 2010

Phys. Chem. Chem. Phys.

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The preparation, characterization and catalytic reactivity of a GaN supported Pt catalyst in the hydrogenation of ethene are presented in this feature article, highlighting the use of in situ characterization of the material properties during sample handling and catalysis by combining temperature programmed reaction with in situ grazing incidence small-angle X-ray scattering and X-ray absorption spectroscopy. The catalysts are found to be sintering resistant at elevated temperatures as well as during reduction and hydrogenation reactions. In contrast to Pt particles of approximately 7 nm diameter, smaller particles of 1.8 nm in size are found to dynamically adapt their shape and oxidation state to the changes in the reaction environment. These smaller Pt particles also showed an initial deactivation in ethene hydrogenation, which is paralleled by the change in the particle shape. The subtle temperature-dependent X-ray absorbance of the 1.8 nm sized Pt particles indicates that subtle variations in the electronic structure induced by the state of reduction by electron tunnelling over the Schottky barrier between the Pt particles and the GaN support can be monitored.

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Ethylene Hydrogenation over Platinum Nanoparticle Array Model Catalysts Fabricated by Electron Beam Lithography: Determination of Active Metal Surface Area

Cited by 140 publications

References 21 publications

Spatially orthogonal chemical functionalization of a hierarchical pore network for catalytic cascade reactions

Spatially orthogonal chemical functionalization of a hierarchical pore network for catalytic cascade reactions

Clusters, surfaces, and catalysis

Combined TPRx, in situ GISAXS and GIXAS studies of model semiconductor-supported platinum catalysts in the hydrogenation of ethene

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