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Bols ML, Ma J, Rammal F, Plessers D, Wu X, Navarro-Jaén S, Heyer AJ, Sels BF, Solomon EI, Schoonheydt RA. In Situ UV-Vis-NIR Absorption Spectroscopy and Catalysis. Chem Rev 2024; 124:2352-2418. [PMID: 38408190 DOI: 10.1021/acs.chemrev.3c00602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
This review highlights in situ UV-vis-NIR range absorption spectroscopy in catalysis. A variety of experimental techniques identifying reaction mechanisms, kinetics, and structural properties are discussed. Stopped flow techniques, use of laser pulses, and use of experimental perturbations are demonstrated for in situ studies of enzymatic, homogeneous, heterogeneous, and photocatalysis. They access different time scales and are applicable to different reaction systems and catalyst types. In photocatalysis, femto- and nanosecond resolved measurements through transient absorption are discussed for tracking excited states. UV-vis-NIR absorption spectroscopies for structural characterization are demonstrated especially for Cu and Fe exchanged zeolites and metalloenzymes. This requires combining different spectroscopies. Combining magnetic circular dichroism and resonance Raman spectroscopy is especially powerful. A multitude of phenomena can be tracked on transition metal catalysts on various supports, including changes in oxidation state, adsorptions, reactions, support interactions, surface plasmon resonances, and band gaps. Measurements of oxidation states, oxygen vacancies, and band gaps are shown on heterogeneous catalysts, especially for electrocatalysis. UV-vis-NIR absorption is burdened by broad absorption bands. Advanced analysis techniques enable the tracking of coking reactions on acid zeolites despite convoluted spectra. The value of UV-vis-NIR absorption spectroscopy to catalyst characterization and mechanistic investigation is clear but could be expanded.
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Affiliation(s)
- Max L Bols
- Laboratory for Chemical Technology (LCT), University of Ghent, Technologiepark Zwijnaarde 125, 9052 Ghent, Belgium
| | - Jing Ma
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Fatima Rammal
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Dieter Plessers
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Xuejiao Wu
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Sara Navarro-Jaén
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Alexander J Heyer
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Bert F Sels
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Robert A Schoonheydt
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
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2
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Heyer AJ, Plessers D, Ma J, Snyder BER, Schoonheydt RA, Sels BF, Solomon EI. Magnetic Exchange Coupling in Zeolite Copper Dimers and Its Contribution to Methane Activation. J Am Chem Soc 2024; 146:6061-6071. [PMID: 38385349 DOI: 10.1021/jacs.3c13295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
The highly reactive binuclear [Cu2O]2+ active site in copper zeolites activates the inert C-H bond of methane at low temperatures, offering a potential solution to reduce methane flaring and mitigate atmospheric methane levels. While substantial progress has been made in understanding the activation of methane by this core, one critical aspect, the active site's spin, has remained undetermined. In this study, we use variable-temperature, variable-field magnetic circular dichroism spectroscopy to define the ground state spin of the [Cu2O]2+ active sites in Cu-CHA and Cu-MFI. This novel approach allows for site-selective determination of the magnetic exchange coupling between the two copper centers of specific [Cu2O]2+ cores in a heterogeneous mixture, circumventing the drawbacks of bulk magnetic techniques. These experimental findings are coupled to density functional theory calculations to elucidate magnetostructural correlations in copper zeolites that are different from those of homogeneous binuclear Cu(II) complexes. The different spin states for the [Cu2O]2+ cores have different reactivities governed by how methane approaches the active site. This introduces a new understanding of zeolite topological control on active site reactivity.
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Affiliation(s)
- Alexander J Heyer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, Leuven B-3001, Belgium
| | - Dieter Plessers
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, Leuven B-3001, Belgium
| | - Jing Ma
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, Leuven B-3001, Belgium
| | - Benjamin E R Snyder
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Robert A Schoonheydt
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, Leuven B-3001, Belgium
| | - Bert F Sels
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, Leuven B-3001, Belgium
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
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3
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Lindquist KP, Eghdami A, Deschene CR, Heyer AJ, Wen J, Smith AG, Solomon EI, Lee YS, Neaton JB, Ryan DH, Karunadasa HI. Stabilizing Au 2+ in a mixed-valence 3D halide perovskite. Nat Chem 2023; 15:1780-1786. [PMID: 37640854 DOI: 10.1038/s41557-023-01305-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 07/24/2023] [Indexed: 08/31/2023]
Abstract
Although Cu2+ is ubiquitous, the relativistic destabilization of the 5d orbitals makes the isoelectronic Au2+ exceedingly rare, typically stabilized only through Au-Au bonding or by using redox non-innocent ligands. Here we report the perovskite Cs4AuIIAuIII2Cl12, an extended solid with mononuclear Au2+ sites, which is stable to ambient conditions and characterized by single-crystal X-ray diffraction. The 2+ oxidation state of Au was assigned using 197Au Mössbauer spectroscopy, electron paramagnetic resonance, and magnetic susceptibility measurements, with comparison to paramagnetic and diamagnetic analogues with Cu2+ and Pd2+, respectively, as well as to density functional theory calculations. This gold perovskite offers an opportunity to study the optical and electronic transport of the uncommon Au2+/3+ mixed-valence state and the characteristics of the elusive Au2+ ion coordinated to simple ligands. Compared with the perovskite Cs2AuIAuIIICl6, which has been studied since the 1920s, Cs4AuIIAuIII2Cl12 exhibits a 0.7 eV reduction in optical absorption onset and a 103-fold increase in electronic conductivity.
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Affiliation(s)
| | - Armin Eghdami
- Department of Physics, University of California Berkeley, Berkeley, CA, USA
| | | | | | - Jiajia Wen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Alexander G Smith
- Department of Physics, University of California Berkeley, Berkeley, CA, USA
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, CA, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA, USA
| | - Young S Lee
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Department of Applied Physics, Stanford University, Stanford, CA, USA
| | - Jeffrey B Neaton
- Department of Physics, University of California Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Kavli Energy NanoSciences Institute at Berkeley, Berkeley, CA, USA
| | - Dominic H Ryan
- Physics Department and Centre for the Physics of Materials, McGill University, Montreal, Quebec, Canada
| | - Hemamala I Karunadasa
- Department of Chemistry, Stanford University, Stanford, CA, USA.
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
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4
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Plessers D, Heyer AJ, Rhoda HM, Bols ML, Solomon EI, Schoonheydt RA, Sels BF. Tuning Copper Active Site Composition in Cu-MOR through Co-Cation Modification for Methane Activation. ACS Catal 2023. [DOI: 10.1021/acscatal.2c05271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Dieter Plessers
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, B-3001Leuven, Belgium
| | - Alexander J. Heyer
- Department of Chemistry, Stanford University, Stanford, California94305, United States
| | - Hannah M. Rhoda
- Department of Chemistry, Stanford University, Stanford, California94305, United States
| | - Max L. Bols
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, B-3001Leuven, Belgium
| | - Edward I. Solomon
- Department of Chemistry, Stanford University, Stanford, California94305, United States
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California94025, United States
| | - Robert A. Schoonheydt
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, B-3001Leuven, Belgium
| | - Bert F. Sels
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, B-3001Leuven, Belgium
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Heyer AJ, Plessers D, Braun A, Rhoda HM, Bols ML, Hedman B, Hodgson KO, Schoonheydt RA, Sels BF, Solomon EI. Methane Activation by a Mononuclear Copper Active Site in the Zeolite Mordenite: Effect of Metal Nuclearity on Reactivity. J Am Chem Soc 2022; 144:19305-19316. [PMID: 36219763 DOI: 10.1021/jacs.2c06269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The direct conversion of methane to methanol would have a wide reaching environmental and industrial impact. Copper-containing zeolites can perform this reaction at low temperatures and pressures at a previously defined O2-activated [Cu2O]2+ site. However, after autoreduction of the copper-containing zeolite mordenite and removal of the [Cu2O]2+ active site, the zeolite is still methane reactive. In this study, we use diffuse reflectance UV-vis spectroscopy, magnetic circular dichroism, resonance Raman spectroscopy, electron paramagnetic resonance, and X-ray absorption spectroscopy to unambiguously define a mononuclear [CuOH]+ as the CH4 reactive active site of the autoreduced zeolite. The rigorous identification of a mononuclear active site allows a reactivity comparison to the previously defined [Cu2O]2+ active site. We perform kinetic experiments to compare the reactivity of the [CuOH]+ and [Cu2O]2+ sites and find that the binuclear site is significantly more reactive. From the analysis of density functional theory calculations, we elucidate that this increased reactivity is a direct result of stabilization of the [Cu2OH]2+ H-atom abstraction product by electron delocalization over the two Cu cations via the bridging ligand. This significant increase in reactivity from electron delocalization over a binuclear active site provides new insights for the design of highly reactive oxidative catalysts.
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Affiliation(s)
- Alexander J Heyer
- Department of Chemistry, Stanford University, Stanford, California94305, United States
| | - Dieter Plessers
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, LeuvenB-3001, Belgium
| | - Augustin Braun
- Department of Chemistry, Stanford University, Stanford, California94305, United States
| | - Hannah M Rhoda
- Department of Chemistry, Stanford University, Stanford, California94305, United States
| | - Max L Bols
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, LeuvenB-3001, Belgium
| | - Britt Hedman
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California94025, United States
| | - Keith O Hodgson
- Department of Chemistry, Stanford University, Stanford, California94305, United States.,Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California94025, United States
| | - Robert A Schoonheydt
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, LeuvenB-3001, Belgium
| | - Bert F Sels
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, LeuvenB-3001, Belgium
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, California94305, United States.,Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California94025, United States
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6
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Rhoda HM, Heyer AJ, Snyder BER, Plessers D, Bols ML, Schoonheydt RA, Sels BF, Solomon EI. Second-Sphere Lattice Effects in Copper and Iron Zeolite Catalysis. Chem Rev 2022; 122:12207-12243. [PMID: 35077641 DOI: 10.1021/acs.chemrev.1c00915] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Transition-metal-exchanged zeolites perform remarkable chemical reactions from low-temperature methane to methanol oxidation to selective reduction of NOx pollutants. As with metalloenzymes, metallozeolites have impressive reactivities that are controlled in part by interactions outside the immediate coordination sphere. These second-sphere effects include activating a metal site through enforcing an "entatic" state, controlling binding and access to the metal site with pockets and channels, and directing radical rebound vs cage escape. This review explores these effects with emphasis placed on but not limited to the selective oxidation of methane to methanol with a focus on copper and iron active sites, although other transition-metal-ion zeolite reactions are also explored. While the actual active-site geometric and electronic structures are different in the copper and iron metallozeolites compared to the metalloenzymes, their second-sphere interactions with the lattice or the protein environments are found to have strong parallels that contribute to their high activity and selectivity.
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Affiliation(s)
- Hannah M Rhoda
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Alexander J Heyer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Benjamin E R Snyder
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Dieter Plessers
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Max L Bols
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Robert A Schoonheydt
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Bert F Sels
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,Photon Science, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
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7
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Jackson RB, Abernethy S, Canadell JG, Cargnello M, Davis SJ, Féron S, Fuss S, Heyer AJ, Hong C, Jones CD, Damon Matthews H, O'Connor FM, Pisciotta M, Rhoda HM, de Richter R, Solomon EI, Wilcox JL, Zickfeld K. Atmospheric methane removal: a research agenda. Philos Trans A Math Phys Eng Sci 2021; 379:20200454. [PMID: 34565221 PMCID: PMC8473948 DOI: 10.1098/rsta.2020.0454] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Atmospheric methane removal (e.g. in situ methane oxidation to carbon dioxide) may be needed to offset continued methane release and limit the global warming contribution of this potent greenhouse gas. Because mitigating most anthropogenic emissions of methane is uncertain this century, and sudden methane releases from the Arctic or elsewhere cannot be excluded, technologies for methane removal or oxidation may be required. Carbon dioxide removal has an increasingly well-established research agenda and technological foundation. No similar framework exists for methane removal. We believe that a research agenda for negative methane emissions-'removal' or atmospheric methane oxidation-is needed. We outline some considerations for such an agenda here, including a proposed Methane Removal Model Intercomparison Project (MR-MIP). This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 1)'.
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Affiliation(s)
- Robert B. Jackson
- Department of Earth System Science, Stanford University, Stanford, CA 94305-2210, USA
- Woods Institute for the Environment, and Precourt Institute for Energy, Stanford University, Stanford, CA 94305-2210, USA
| | - Sam Abernethy
- Department of Earth System Science, Stanford University, Stanford, CA 94305-2210, USA
- Department of Applied Physics, Stanford University, Stanford, CA, USA
| | - Josep G. Canadell
- Global Carbon Project, CSIRO Oceans and Atmosphere, Canberra, Australian Capital Territory 2601, Australia
| | - Matteo Cargnello
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA, USA
| | - Steven J. Davis
- Department of Earth System Science, University of California at Irvine, Irvine, CA 92697, USA
| | - Sarah Féron
- Department of Earth System Science, Stanford University, Stanford, CA 94305-2210, USA
| | - Sabine Fuss
- Mercator Research Institute on Global Commons and Climate Change, Berlin, Germany
- Geographisches Institut, Humboldt Universität zu, Berlin, Germany
| | | | - Chaopeng Hong
- Department of Earth System Science, University of California at Irvine, Irvine, CA 92697, USA
| | - Chris D. Jones
- Met Office Hadley Centre, FitzRoy Road, Exeter EX1 3PB, UK
| | - H. Damon Matthews
- Department of Geography Planning and Environment, Concordia University, Montreal, Quebec, Canada
| | | | - Maxwell Pisciotta
- Chemical and Biomolecular Engineering Department, University of Pennsylvania, Pennsylvania, PA, USA
| | - Hannah M. Rhoda
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Renaud de Richter
- Ecole Nationale Supérieure de Chimie de Montpellier, Montpellier, Languedoc-Roussillon FR, USA
| | - Edward I. Solomon
- Department of Chemistry, Stanford University, Stanford, CA, USA
- SLAC National Accelerator Laboratory, Stanford University, Stanford, CA, USA
| | - Jennifer L. Wilcox
- Chemical and Biomolecular Engineering Department, University of Pennsylvania, Pennsylvania, PA, USA
| | - Kirsten Zickfeld
- Department of Geography, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
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8
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Connor BA, Smaha RW, Li J, Gold-Parker A, Heyer AJ, Toney MF, Lee YS, Karunadasa HI. Alloying a single and a double perovskite: a Cu +/2+ mixed-valence layered halide perovskite with strong optical absorption. Chem Sci 2021; 12:8689-8697. [PMID: 34257867 PMCID: PMC8246118 DOI: 10.1039/d1sc01159f] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 05/13/2021] [Indexed: 11/21/2022] Open
Abstract
Introducing heterovalent cations at the octahedral sites of halide perovskites can substantially change their optoelectronic properties. Yet, in most cases, only small amounts of such metals can be incorporated as impurities into the three-dimensional lattice. Here, we exploit the greater structural flexibility of the two-dimensional (2D) perovskite framework to place three distinct stoichiometric cations in the octahedral sites. The new layered perovskites AI 4[CuII(CuIInIII)0.5Cl8] (1, A = organic cation) may be derived from a CuI-InIII double perovskite by replacing half of the octahedral metal sites with Cu2+. Electron paramagnetic resonance and X-ray absorption spectroscopy confirm the presence of Cu2+ in 1. Crystallographic studies demonstrate that 1 represents an averaging of the CuI-InIII double perovskite and CuII single perovskite structures. However, whereas the highly insulating CuI-InIII and CuII perovskites are colorless and yellow, respectively, 1 is black, with substantially higher electronic conductivity than that of either endmember. We trace these emergent properties in 1 to intervalence charge transfer between the mixed-valence Cu centers. We further propose a tiling model to describe how the Cu+, Cu2+, and In3+ coordination spheres can pack most favorably into a 2D perovskite lattice, which explains the unusual 1 : 2 : 1 ratio of these cations found in 1. Magnetic susceptibility data of 1 further corroborate this packing model. The emergence of enhanced visible light absorption and electronic conductivity in 1 demonstrates the importance of devising strategies for increasing the compositional complexity of halide perovskites.
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Affiliation(s)
- Bridget A Connor
- Department of Chemistry, Stanford University Stanford California 94305 USA
| | - Rebecca W Smaha
- Department of Chemistry, Stanford University Stanford California 94305 USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory Menlo Park California 94025 USA
| | - Jiayi Li
- Department of Chemistry, Stanford University Stanford California 94305 USA
| | - Aryeh Gold-Parker
- Department of Chemistry, Stanford University Stanford California 94305 USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory Menlo Park California 94025 USA
| | - Alexander J Heyer
- Department of Chemistry, Stanford University Stanford California 94305 USA
| | - Michael F Toney
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory Menlo Park California 94025 USA
- Department of Chemical and Biological Engineering, University of Colorado Boulder Boulder CO 80309 USA
| | - Young S Lee
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory Menlo Park California 94025 USA
- Department of Applied Physics, Stanford University Stanford California 94305 USA
| | - Hemamala I Karunadasa
- Department of Chemistry, Stanford University Stanford California 94305 USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory Menlo Park California 94025 USA
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9
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Rhoda HM, Plessers D, Heyer AJ, Bols ML, Schoonheydt RA, Sels BF, Solomon EI. Spectroscopic Definition of a Highly Reactive Site in Cu-CHA for Selective Methane Oxidation: Tuning a Mono-μ-Oxo Dicopper(II) Active Site for Reactivity. J Am Chem Soc 2021; 143:7531-7540. [PMID: 33970624 DOI: 10.1021/jacs.1c02835] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using UV-vis and resonance Raman spectroscopy, we identify a [Cu2O]2+ active site in O2 and N2O activated Cu-CHA that reacts with methane to form methanol at low temperature. The Cu-O-Cu angle (120°) is smaller than that for the [Cu2O]2+ core on Cu-MFI (140°), and its coordination geometry to the zeolite lattice is different. Site-selective kinetics obtained by operando UV-vis show that the [Cu2O]2+ core on Cu-CHA is more reactive than the [Cu2O]2+ site in Cu-MFI. From DFT calculations, we find that the increased reactivity of Cu-CHA is a direct reflection of the strong [Cu2OH]2+ bond formed along the H atom abstraction reaction coordinate. A systematic evaluation of these [Cu2O]2+ cores reveals that the higher O-H bond strength in Cu-CHA is due to the relative orientation of the two planes of the coordinating bidentate O-Al-O T-sites that connect the [Cu2O]2+ core to the zeolite lattice. This work along with our earlier study ( J. Am. Chem. Soc, 2018, 140, 9236-9243) elucidates how zeolite lattice constraints can influence active site reactivity.
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Affiliation(s)
- Hannah M Rhoda
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Dieter Plessers
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Alexander J Heyer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Max L Bols
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Robert A Schoonheydt
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Bert F Sels
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,Photon Science, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
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10
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Heyer AJ, Shivokevich PJ, Hooe SL, Welch KD, Harman WD, Machan CW. Reversible modulation of the redox characteristics of acid-sensitive molybdenum and tungsten scorpionate complexes. Dalton Trans 2018; 47:6323-6332. [DOI: 10.1039/c8dt00598b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The large-scale synthesis of the scorpionate ligand Ttz (hydrotris(1,2,4-triazol-1-yl)borate) is reported, as well as syntheses of Group VI complexes K[M(L)(CO)3] and M(L)(NO)(CO)2, (M = Mo or W).
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Affiliation(s)
| | | | - Shelby L. Hooe
- Department of Chemistry
- University of Virginia
- Charlottesville
- USA
| | - Kevin D. Welch
- Department of Chemistry
- University of Virginia
- Charlottesville
- USA
| | - W. Dean Harman
- Department of Chemistry
- University of Virginia
- Charlottesville
- USA
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