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Sobotík, P.; Setvín, Martin; Zimmermann, Petr; Kocán, Pavel; Ošt’ádal, Ivan; Mutombo, Pingo; Ondráček, Martin; Jelı́nek, Pavel

doi:10.1103/physrevb.88.205406

Cited by 9 publications

(4 citation statements)

References 25 publications

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“…In the analysis of single-atom alloys, palladium atoms isolated in a copper lattice were found to be almost electronically identical to their host atoms 113 . The study of In-Sn bimetallic chains on a single crystal silicon surface identified the preferential formation of In-Sn dimers stabilized by charge transfer to neighbouring In-In dimers, which induces the emergence of localized electronic states at, or slightly above, the Fermi level 114 .…”

Section: Electronic Structurementioning

confidence: 99%

Atomically precise control in the design of low-nuclearity supported metal catalysts

Mitchell

Pérez‐Ramírez

2021

Nat Rev Mater

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Nanostructured catalysts incorporating supported metal atoms or small clusters of defined size and chemical composition attract considerable attention because of their potential to maximize resource efficiency. When optimally assembled, all the metal nuclei can participate in the catalytic cycle with properties tailored to deliver high specific activity and stable performance. Over the past decade, both the number and diversity of reported systems have exploded as researchers attempt to control the nanostructure with increasing atomic precision.Nonetheless, spatially resolving the architecture and properties of supported low-nuclearity catalysts remains challenging using existing analytical methods. After identifying general structural features of this advanced family of catalytic materials, including the composition, nuclearity, coordination environment, and location, as well as dynamic effects in reactive environments, our contribution critically examines progress in their control and understanding. State-of-the-art experimental and theoretical approaches for the characterization are explored, addressing strengths and limitations through recent case studies.Finally, we outline directions for future work that will cross frontiers in the design of catalytic materials, which will be indispensable for developing high-performing new architectures for sustainable technologies.Accordingly, the development of high-performance catalysts based on supported metal atoms or clusters requires an ability to precisely control the assembly and structure of active sites and relate this to their associated reactivity patterns. Success relies on the availability of techniques that can discriminate several fundamental properties. However, the spatial resolution of these tiny species at the atomic scale still poses an incredible challenge. The fact that practically relevant host materials typically have irregular three-dimensional morphologies and exhibit non-uniform surface structures and compositions compounds the difficulty because of the high resulting polydispersity of coordination sites. There is also growing awareness that small metal entities often contain chemically distinct atoms, for example, p-block elements or halogens. These atoms may come from the carrier or the chemisorption of simple ligands and determine their stability and associated properties. For this reason, most fundamental insights about the effects of nuclearity on structureperformance relationships derive from the study of simplified systems such as clusters in the gas phase 12 or anchored on single-crystal surfaces 6 . Besides, under reaction conditions, for example at elevated temperature, pressure, potential, and in the presence of distinct chemical species, various structural isomers of low-nuclearity species may coexist and interconvert from one to another, a phenomenon referred to as fluxionality 13 .The potential for emerging low-nuclearity catalysts to surpass the performance of conventionally supported metal nanoparticles together with the additio...

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Section: Electronic Structurementioning

confidence: 99%

Atomically precise control in the design of low-nuclearity supported metal catalysts

Mitchell

Pérez‐Ramírez

2021

Nat Rev Mater

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“…As a representative example of the relevance of these methods toward understanding of pair-sites, isolated indium-tin and indium-indium dimers, as well as chains comprising these, were imaged by STM on atomically flat Si(001). 57 In this investigation, a combination of STS and the calculated local projected density of states was used to demonstrate that the local relative proximities of the dimeric species (and the associated charge transfer this facilitated) was determinative of whether the cluster could be characterized as metallic or semiconducting.…”

Section: Scanning Probe Techniquesmentioning

confidence: 99%

Supported Metal Pair-Site Catalysts

et al. 2020

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Complexes with neighboring metal centers and their analogues on surfaces are drawing increasing attention as catalysts. These include molecular homogeneous catalysts incorporating various ligands; enzymes; and solids that include pairs of metal atoms mounted on supports.Catalysts in this broad class are active for numerous reactions and offer unexplored opportunities to address challenging reactions, such as oxidation of methane and oxidation of water in artificial photosynthesis. The subject of supported metal pair-site catalysts is in its infancy, facing challenges in (a) precise synthesis, (b) structure determination at the atomic scale, and (c) stabilization in reactive atmospheres. In this Perspective, we summarize key characteristics of molecular and enzymatic catalysts that incorporate neighboring metal centers and build on this foundation to assess the emerging literature of metal pair-site catalysts on various supports. The supported catalysts include those synthesized by anchoring molecular dinuclear precursors to support surfaces and those synthesized by selective formation of dinuclear surface species from mononuclear surface species. Examples of metals in this class are rhodium and iridium, and

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“…For instance, defined In−Sn heterodimers and In–In homodimers and chains of these on Si(001) have been investigated by STM. [ 262 ] More recently, partially dissociated water dimers on the O 2 evolution active hematite interface were confirmed through non‐contact atomic force microscopy (AFM), combined with other techniques. [ 263 ] CO adsorption on model single atom Ir adatoms on a Fe 3 O 4 (001) support was demonstrated by STM, non‐contact AFM and DFT ( Figure 20 a–c), [ 260 ] while in separate work Cu adatoms on the same support was proven by measuring the relative change in height of the Cu before and after CO adsorption via STM.…”

Section: Advanced Characterizationmentioning

confidence: 99%

Dual‐Metal Atom Electrocatalysts: Theory, Synthesis, Characterization, and Applications

Pedersen

Barrio

et al. 2021

Advanced Energy Materials

106

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a required reduction in emissions per unit production of 75% by 2050 in order to have a 50% chance of limiting global mean temperature rise by 2 °C compared to pre-industrial levels. [1,2] Improvements in the field of electrocatalysts, especially in relation to electrolyzers and fuel cells, will help these devices become part of the solution to the looming sustainable energy and chemical production needs. [3] For these devices to be entirely renewable, H 2 (and O 2 ) needs to be produced by water splitting in electrolyzers through H 2 and O 2 evolution (green hydrogen production), rather than from methane reforming (grey hydrogen production). [4,5] H 2 can then be used in electrochemical O 2 reduction in fuel cells to produce electricity. [6,7] Meanwhile, electrochemical reduction of N 2 to NH 3 can provide a sustainable means to a critical fertilization source for the agricultural industry and a carrier for H 2 . [8] Moreover, a way of producing value-added products and a "circular economy" for industry from CO 2 emissions is via the electrocatalytically driven CO 2 reduction, which converts CO 2 to essential feedstocks, such as ethylene or ethanol for the chemical industry. [9] Low-temperature fuel cells and electrolyzers typically utilize catalysts based on platinum group metal (PGM) nanoparticles, [10] which limits device commercialization due to increasing global demand, low uptake of recycling, and high cost of PGMs. [11] Consequently, many researchers have turned their attention to reducing PGM loading or entirely replacing them with lower-cost earth-abundant metals, such as Fe, Cu, Ni, Co, Mn, and, most recently, Sn. [12] Regardless of the catalyst composition, improvements in the electrochemical activity have been highly sought after with two general options available; increasing the number of accessible catalytic sites and/or increasing the intrinsic activity of the catalytic sites. [13] Many different catalyst designs have been explored in order to raise the activity, such as alloying [14] or nanostructuring. [15] While increasing the density of catalytic sites improves activity, this method becomes physically limited when catalyst loading affects charge and mass transport. [13] Thus, improving the activity per catalytic site (intrinsic activity) through controlling local geometry and electronic structure has garnered research attention, with successful methods including shrinking the catalytic site down to atomic scale, as well as locally introducing light heteroatoms or hosting the catalytic site at edges. [10,[16][17][18] Electrochemical clean energy conversion and the production of sustainable chemicals are critical in the journey to realizing a truly sustainable society. To progress electrochemical storage and conversion devices to commercialization, improving the electrocatalyst performance and cost are of utmost importance. Research into dual-metal atom catalysts (DACs) is rising in prominence due to the advantages of these sites over single-metal atom catalysts (SACs), such as breaking scaling ...

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Emergence of state at Fermi level due to the formation of In-Sn heterodimers on Si(100)-2×1

Cited by 9 publications

References 25 publications

Atomically precise control in the design of low-nuclearity supported metal catalysts

Atomically precise control in the design of low-nuclearity supported metal catalysts

Supported Metal Pair-Site Catalysts

Dual‐Metal Atom Electrocatalysts: Theory, Synthesis, Characterization, and Applications

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