Dry Dehydrogenation of Ethanol on Pt–Cu Single Atom Alloys

Wang, Zhitao; Hoyt, Robert A.; El-Soda, Mostafa; Madix, Robert J.; Kaxiras, Efthimios; Sykes, E. Charles H.

doi:10.1007/s11244-017-0856-3

Cited by 50 publications

(65 citation statements)

References 30 publications

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“…The lowest lying transition state varies across the different SAA surfaces, with the majority of SAAs with Au hosts being "methanol-like" and the majority of those with Ag or Cu hosts being "methoxy-like". Dissociation on each of the Ni-doped SAAs proceeds via the We note here that Pt/Cu SAAs can perform highly efficient and selective dry and water co-catalysed dehydrogenation of simple alcohols to aldehydes 7,19 , thereby suggesting this may also be the case for other SAA surfaces with similar energetics.…”

Section: Methanol Dissociationmentioning

confidence: 72%

“…3-4, 8, 15-18 Additionally, Pt/Cu SAAs have shown high resistance to coke formation during C-H activation and subsequent C-C coupling reactions and can perform efficient dry dehydrogenation of alcohols to carbonyls. 5,[9][10][19][20] SAAs offer strong resistance to catalytic poisoning by CO [21][22] ; yet, as alluded to above, still retain the ability to catalyse numerous chemistries with high activity at low temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Elucidating the Stability and Reactivity of Surface Intermediates on Single-Atom Alloy Catalysts

et al. 2018

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Doping isolated single atoms of a platinum group metal into the surface of a noble metal host is sufficient to dramatically improve the activity of the unreactive host yet also facilitates the retention of the host's high reaction selectivity in numerous catalytic reactions. The atomically dispersed highly active sites in these Single Atom Alloy (SAA) materials are capable of performing facile bond activations allowing for the uptake of species onto the surface, and the subsequent spillover of adspecies onto the noble host material, where selective catalysis can be performed. For example, SAAs have been shown to activate C-H bonds at low temperatures without coke formation, as well as selectively hydrogenating unsaturated hydrocarbons with excellent activity. However to date, only a small subset of SAAs has been synthesised experimentally and it is unclear which metallic combinations may best catalyse which chemical reactions. To shed light on this issue, we have performed a widespread screening study using density functional theory to elucidate the fundamental adsorptive and catalytic properties of 12 SAAs (Ni-, Pd-, Pt-and Rh-doped Cu(111), Ag(111) and Au(111)). We considered the interaction of these SAAs with a variety of adsorbates often found in catalysis, and computed reaction mechanisms for the activation of several catalytically relevant species (H2, CH4, NH3, CH3OH and CO2) by SAAs. Finally, we discuss the applicability of thermochemical linear scaling and the Brønsted-Evans-Polanyi relationship to SAA systems, demonstrating that SAAs combine weak binding with low activation energies to give enhanced catalytic behaviour over their monometallic counterparts. This work will ultimately facilitate the discovery and development of SAAs, serving as a guide to experimentalists and theoreticians alike.

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Section: Methanol Dissociationmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Elucidating the Stability and Reactivity of Surface Intermediates on Single-Atom Alloy Catalysts

et al. 2018

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“…[72][73][84][85][86][87][88][89] DFT has also been used to explain how SAAs can exhibit combined low temperature C-H activation and coke resistance 65 (see section 3), to justify why SAAs have excellent tolerance to poisoning by CO, 90 to aid in SAA surface characterization, 75 and to rationalize their ability to perform dry, nonoxidative dehydrogenation of alcohols. 79 Most recently, simulation using DFT has become more exploratory. 53,[90][91][92] Progress in applying theory and simulation to SAA systems has now reached a pivotal point where it is not only being used to explain experimental findings, but to make predictions.…”

mentioning

confidence: 99%

Lonely Atoms with Special Gifts: Breaking Linear Scaling Relationships in Heterogeneous Catalysis with Single-Atom Alloys

Darby

Stamatakis

Michaelides

et al. 2018

J. Phys. Chem. Lett.

252

274

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We discuss a simple yet effective strategy for escaping traditional linear scaling relations in heterogeneous catalysis with highly dilute bimetallic alloys known as single-atom alloys (SAAs). These systems, in which a reactive metal is atomically dispersed in a less reactive host, were first demonstrated with the techniques of surface science to be active and selective for hydrogenation reactions. Informed by these early results, PdCu and PtCu SAA nanoparticle hydrogenation catalysts were shown to work under industrially relevant conditions. To efficiently survey the many potential metal combinations and reactions, simulation is crucial for making predictions about reactivity and guiding experimental focus on the most promising candidate materials. This recent work reveals that the high surface chemical heterogeneity of SAAs can result in significant deviations from Brønsted-Evans-Polanyi scaling relationships for many key reaction steps. These recent insights into SAAs and their ability to break linear scaling relations motivate discovery of novel alloy catalysts.

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“…[56] The method was used to make dilute alloys, including so-called single atom alloys (SAA) that consist of atomically dispersed metals typified by platinum in γ-Al 2 O 3 -supported nanoparticles of coinage metals typified by copper. [17,18,[57][58][59][60][61][62][63][64] Loadings were 0.1(Pt)/14(Cu), by weight and 0.2(Pt)/12(Cu) by weight. Numerous combinations of dispersed metals (M 1 ) and host metals (M 2 ) can be made by GR, provided that the reduction potential of M 2 is lower than that of M 1 .…”

Section: Galvanic Replacement (Gr)mentioning

confidence: 99%

“…Depending on the conditions, various coverages of platinum on single-crystal supports have been obtained, and atomic dispersions of metal have been achieved at low metal loadings, such as 0.01 monolayers of platinum. [17,18,[57][58][59][60][61]63,64,106,107] Figure 5. Schematic illustration of a) mobile platinum species to provide oxygen needed to bind to under-coordinated Ce 3+ sites at step edges of CeO 2 .…”

Section: Electron Beam-induced Evaporation (Ebe)mentioning

confidence: 99%

Prototype Atomically Dispersed Supported Metal Catalysts: Iridium and Platinum

Chen

Sun

Gates

2020

Small

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Heterogeneous catalysis is the central enabling technology of fossil fuel conversion, chemical production, and vehicular and power plant emissions clean-up. Many of the catalysts are precious metals finely dispersed on porous high-area supports, such as metal oxides, zeolites, and carbon. The metals are usually present as zerovalent nanoparticles, and when the particles are made When metal nanoparticles on supports are made smaller and smaller-to the limit of atomic dispersion-they become cationic and take on new catalytic properties that are only recently being discovered. The synthesis of these materials is reviewed, including their structure characterization-especially by atomic-resolution electron microscopy and X-ray absorption and infrared spectroscopies-and relationships between structure and catalyst performance, for reactions including hydrogenations, oxidations, and the water gas shift. Structure determination is challenging because of the intrinsic nonuniformity of the support surfaces-and therefore the structures on them-but fundamental understanding has advanced rapidly, benefiting from nearly uniform catalysts consisting of metals on well-defined-crystalline-supports and their characterization by spectroscopy and microscopy. Recent advances in atomic-resolution electron microscopy have spurred the field, providing stunning images and deep insights into structure. The iridium catalysts have typically been made from organoiridium precursors, opening the way to understanding and control of the metal-support bonding and ligands on the metal, including catalytic reaction intermediates. Platinum catalysts are usually made with less precision, from salt precursors, but they catalyze a wider array of reactions than the iridium, typically being stable at higher temperatures and seemingly offering rich prospect for discovery of new catalysts.smaller to the atomic limit, the metals become cations anchored through metaloxygen or metal-carbon bonds. When all the metal atoms are accessible to reactants, they function with maximum efficiency and economy, and they have properties different from those in nanoparticles.Atomically dispersed supported metal catalysts have a long scientific and technological history. [1] Prominent industrial catalysts include oxophilic metals present as cations on oxide supports, illustrated by chromium complexes on silica for ethylene polymerization [2] and titanium cations in zeolite frameworks for propylene epoxidation. [3] However, the metals most widely applied in supported catalysts are noble-and expensive-typified by platinum and iridium. These are applied as supported nanoparticles. But now there is an explosion of research on atomically dispersed platinum and iridium. We assess it here. The intense interest reflects powerful, newly developed methods for fundamental research and tantalizing, yet unrealized, prospects for new applications of this class of material. Reports of supported platinum catalysts have long included high-resolution transmission electron microscopy (TEM) im...

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Dry Dehydrogenation of Ethanol on Pt–Cu Single Atom Alloys

Cited by 50 publications

References 30 publications

Elucidating the Stability and Reactivity of Surface Intermediates on Single-Atom Alloy Catalysts

Elucidating the Stability and Reactivity of Surface Intermediates on Single-Atom Alloy Catalysts

Lonely Atoms with Special Gifts: Breaking Linear Scaling Relationships in Heterogeneous Catalysis with Single-Atom Alloys

Prototype Atomically Dispersed Supported Metal Catalysts: Iridium and Platinum

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