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Schumann J, Stamatakis M, Michaelides A, Réocreux R. Ten-electron count rule for the binding of adsorbates on single-atom alloy catalysts. Nat Chem 2024; 16:749-754. [PMID: 38263384 PMCID: PMC11087240 DOI: 10.1038/s41557-023-01424-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 12/14/2023] [Indexed: 01/25/2024]
Abstract
Single-atom alloys have recently emerged as highly active and selective alloy catalysts. Unlike pure metals, single-atom alloys escape the well-established conceptual framework developed nearly three decades ago for predicting catalytic performance. Although this offers the opportunity to explore so far unattainable chemistries, this leaves us without a simple guide for the design of single-atom alloys able to catalyse targeted reactions. Here, based on thousands of density functional theory calculations, we reveal a 10-electron count rule for the binding of adsorbates on the dopant atoms, usually the active sites, of single-atom alloy surfaces. A simple molecular orbital approach rationalizes this rule and the nature of the adsorbate-dopant interaction. In addition, our intuitive model can accelerate the rational design of single-atom alloy catalysts. Indeed, we illustrate how the unique insights provided by the electron count rule help identify the most promising dopant for an industrially relevant hydrogenation reaction, thereby reducing the number of potential materials by more than one order of magnitude.
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Affiliation(s)
- Julia Schumann
- Thomas Young Centre and Department of Chemical Engineering, University College London, London, UK
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- Physics Department and IRIS Adlershof, Humboldt Universität zu Berlin, Berlin, Germany
| | - Michail Stamatakis
- Thomas Young Centre and Department of Chemical Engineering, University College London, London, UK
- Department of Chemistry, University of Oxford, Oxford, UK
| | - Angelos Michaelides
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Romain Réocreux
- Thomas Young Centre and Department of Chemical Engineering, University College London, London, UK.
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK.
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2
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Kress PL, Zhang S, Wang Y, Çınar V, Friend CM, Sykes ECH, Montemore MM. A Priori Design of Dual-Atom Alloy Sites and Experimental Demonstration of Ethanol Dehydrogenation and Dehydration on PtCrAg. J Am Chem Soc 2023; 145. [PMID: 36888984 PMCID: PMC10119928 DOI: 10.1021/jacs.2c13577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Indexed: 03/10/2023]
Abstract
Single-atom catalysts have received significant attention for their ability to enable highly selective reactions. However, many reactions require more than one adjacent site to align reactants or break specific bonds. For example, breaking a C-O or O-H bond may be facilitated by a dual site containing an oxophilic element and a carbophilic or "hydrogenphilic" element that binds each molecular fragment. However, design of stable and well-defined dual-atom sites with desirable reactivity is difficult due to the complexity of multicomponent catalytic surfaces. Here, we describe a new type of dual-atom system, trimetallic dual-atom alloys, which were designed via computation of the alloying energetics. Through a broad computational screening we discovered that Pt-Cr dimers embedded in Ag(111) can be formed by virtue of the negative mixing enthalpy of Pt and Cr in Ag and the favorable interaction between Pt and Cr. These dual-atom alloy sites were then realized experimentally through surface science experiments that enabled the active sites to be imaged and their reactivity related to their atomic-scale structure. Specifically, Pt-Cr sites in Ag(111) can convert ethanol, whereas PtAg and CrAg are unreactive toward ethanol. Calculations show that the oxophilic Cr atom and the hydrogenphilic Pt atom act synergistically to break the O-H bond. Furthermore, ensembles with more than one Cr atom, present at higher dopant loadings, produce ethylene. Our calculations have identified many other thermodynamically favorable dual-atom alloy sites, and hence this work highlights a new class of materials that should offer new and useful chemical reactivity beyond the single-atom paradigm.
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Affiliation(s)
- Paul L. Kress
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Shengjie Zhang
- Department
of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| | - Yicheng Wang
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Volkan Çınar
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Cynthia M. Friend
- Department
of Chemistry and Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - E. Charles H. Sykes
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Matthew M. Montemore
- Department
of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
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3
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Rosen AS, Vijay S, Persson KA. Free-atom-like d states beyond the dilute limit of single-atom alloys. Chem Sci 2023; 14:1503-1511. [PMID: 36794204 PMCID: PMC9906637 DOI: 10.1039/d2sc05772g] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/13/2023] [Indexed: 01/21/2023] Open
Abstract
Through a data-mining and high-throughput density functional theory approach, we identify a diverse range of metallic compounds that are predicted to have transition metals with "free-atom-like" d states that are highly localized in terms of their energetic distribution. Design principles that favor the formation of localized d states are uncovered, among which we note that site isolation is often necessary but that the dilute limit, as in most single-atom alloys, is not a pre-requisite. Additionally, the majority of localized d state transition metals identified from the computational screening study exhibit partial anionic character due to charge transfer from neighboring metal species. Using CO as a representative probe molecule, we show that localized d states for Rh, Ir, Pd, and Pt tend to reduce the binding strength of CO compared to their pure elemental analogues, whereas this does not occur as consistently for the Cu binding sites. These trends are rationalized through the d-band model, which suggests that the significantly reduced d-band width results in an increased orthogonalization energy penalty upon CO chemisorption. With the multitude of inorganic solids that are predicted to have highly localized d states, the results of the screening study are likely to result in new avenues for heterogeneous catalyst design from an electronic structure perspective.
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Affiliation(s)
- Andrew S. Rosen
- Department of Materials Science and Engineering, University of California, BerkeleyBerkeleyCalifornia94720USA,Miller Institute for Basic Research in Science, University of California, BerkeleyBerkeleyCalifornia 94720USA,Materials Science Division, Lawrence Berkeley National LaboratoryBerkeleyCalifornia 94720USA
| | - Sudarshan Vijay
- Department of Materials Science and Engineering, University of California, BerkeleyBerkeleyCalifornia94720USA,Materials Science Division, Lawrence Berkeley National LaboratoryBerkeleyCalifornia 94720USA
| | - Kristin A. Persson
- Department of Materials Science and Engineering, University of California, BerkeleyBerkeleyCalifornia94720USA,Molecular Foundry, Lawrence Berkeley National LaboratoryBerkeleyCalifornia 94720USA
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Zhang S, Sykes ECH, Montemore MM. Tuning reactivity in trimetallic dual-atom alloys: molecular-like electronic states and ensemble effects. Chem Sci 2022; 13:14070-14079. [PMID: 36540824 PMCID: PMC9728513 DOI: 10.1039/d2sc03650a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 11/12/2022] [Indexed: 10/11/2023] Open
Abstract
Single-atom alloys (SAAs) have drawn significant attention in recent years due to their excellent catalytic properties. Controlling the geometry and electronic structure of this type of localized catalytic active site is of fundamental and technological importance. Dual-atom alloys (DAAs) consisting of a heterometallic dimer embedded in the surface layer of a metal host would bring increased tunability and a larger active site, as compared to SAAs. Here, we use computational studies to show that DAAs allow tuning of the active site electronic structure and reactivity. Interestingly, combining two SAAs into a dual-atom site can result in molecular-like hybridization by virtue of the free-atom-like electronic d states exhibited by many SAAs. DAAs can inherit the weak d-d interaction between dopants and hosts from the constituent SAAs, but exhibit new electronic and reactive properties due to dopant-dopant interactions in the DAA. We identify many heterometallic DAAs that we predict to be more stable than either the constituent SAAs or homometallic dual-atom sites of each dopant. We also show how both electronic and ensemble effects can modify the strength of CO adsorption. Because of the molecular-like interactions that can occur, DAAs require a different approach for tuning chemical properties compared to what is used for previous classes of alloys. This work provides insights into the unique catalytic properties of DAAs, and opens up new possibilities for tailoring localized and well-defined catalytic active sites for optimal reaction pathways.
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Affiliation(s)
- Shengjie Zhang
- Department of Chemical and Biomolecular Engineering, Tulane University New Orleans LA 70118 USA
| | | | - Matthew M Montemore
- Department of Chemical and Biomolecular Engineering, Tulane University New Orleans LA 70118 USA
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Lee JD, Qi Z, Foucher AC, Ngan HT, Dennis K, Cui J, Sadykov II, Crumlin EJ, Sautet P, Stach EA, Friend CM, Madix RJ, Biener J. Facilitating Hydrogen Dissociation over Dilute Nanoporous Ti-Cu Catalysts. J Am Chem Soc 2022; 144:16778-16791. [PMID: 36054824 DOI: 10.1021/jacs.2c00830] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dissociation of H2 is an essential elementary step in many industrial chemical transformations, typically requiring precious metals. Here, we report a hierarchical nanoporous Cu catalyst doped with small amounts of Ti (npTiCu) that increases the rate of H2-D2 exchange by approximately one order of magnitude compared to the undoped nanoporous Cu (npCu) catalyst. The promotional effect of Ti was measured via steady-state H2-D2 exchange reaction experiments under atmospheric pressure flow conditions in the temperature range of 300-573 K. Pretreatment with flowing H2 is required for stable catalytic performance, and two temperatures, 523 and 673 K, were investigated. The experimentally determined H2-D2 exchange rate is 5-7 times greater for npTiCu vs the undoped Cu material under optimized pretreatment and reaction temperatures. The H2 pretreatment leads to full reduction of Cu oxide and partial reduction of surface Ti oxide species present in the as-prepared catalyst as demonstrated using in situ ambient pressure X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. The apparent activation energies and pre-exponential factors measured for H2-D2 exchange are substantially different for Ti-doped vs undoped npCu catalysts. Density functional theory calculations suggest that isolated, metallic Ti atoms on the surface of the Cu host can act as the active surface sites for hydrogen recombination. The increase in the rate of exchange above that of pure Cu is caused primarily by a shift in the rate-determining step from dissociative adsorption on Cu to H/D atom recombination on Ti-doped Cu, with the corresponding decrease in activation entropy that it produces.
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Affiliation(s)
- Jennifer D Lee
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Zhen Qi
- Materials Science Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Alexandre C Foucher
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Hio Tong Ngan
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Kevin Dennis
- Division of Materials Science & Engineering, Ames Laboratory, Ames, Iowa 50010, United States
| | - Jun Cui
- Division of Materials Science & Engineering, Ames Laboratory, Ames, Iowa 50010, United States
| | | | - Ethan J Crumlin
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Philippe Sautet
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States.,Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Eric A Stach
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Cynthia M Friend
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.,John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Robert J Madix
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Juergen Biener
- Materials Science Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
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