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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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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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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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Bols ML, Devos J, Rhoda HM, Plessers D, Solomon EI, Schoonheydt RA, Sels BF, Dusselier M. Selective Formation of α-Fe(II) Sites on Fe-Zeolites through One-Pot Synthesis. J Am Chem Soc 2021; 143:16243-16255. [PMID: 34570975 DOI: 10.1021/jacs.1c07590] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
α-Fe(II) active sites in iron zeolites catalyze N2O decomposition and form highly reactive α-O that selectively oxidizes unreactive hydrocarbons, such as methane. How these α-Fe(II) sites are formed remains unclear. Here different methods of iron introduction into zeolites are compared to derive the limiting factors of Fe speciation to α-Fe(II). Postsynthetic iron introduction procedures on small pore zeolites suffer from limited iron diffusion and dispersion leading to iron oxides. In contrast, by introducing Fe(III) in the hydrothermal synthesis mixture of the zeolite (one-pot synthesis) and the right treatment, crystalline CHA can be prepared with >1.6 wt % Fe, of which >70% is α-Fe(II). The effect of iron on the crystallization is investigated, and the intermediate Fe species are tracked using UV-vis-NIR, FT-IR, and Mössbauer spectroscopy. These data are supplemented with online mass spectrometry in each step, with reactivity tests in α-O formation and with methanol yields in stoichiometric methane activation at room temperature and pressure. We recover up to 134 μmol methanol per gram in a single cycle through H2O/CH3CN extraction and 183 μmol/g through steam desorption, a record yield for iron zeolites. A general scheme is proposed for iron speciation in zeolites through the steps of drying, calcination, and activation. The formation of two cohorts of α-Fe(II) is discovered, one before and one after high temperature activation. We propose the latter cohort depends on the reshuffling of aluminum in the zeolite lattice to accommodate thermodynamically favored α-Fe(II).
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Affiliation(s)
- Max L Bols
- Department of Microbial and Molecular Systems, KU Leuven, 3001 Heverlee, Belgium
| | - Julien Devos
- Department of Microbial and Molecular Systems, KU Leuven, 3001 Heverlee, Belgium
| | - Hannah M Rhoda
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Dieter Plessers
- Department of Microbial and Molecular Systems, KU Leuven, 3001 Heverlee, Belgium
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Robert A Schoonheydt
- Department of Microbial and Molecular Systems, KU Leuven, 3001 Heverlee, Belgium
| | - Bert F Sels
- Department of Microbial and Molecular Systems, KU Leuven, 3001 Heverlee, Belgium
| | - Michiel Dusselier
- Department of Microbial and Molecular Systems, KU Leuven, 3001 Heverlee, Belgium
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Snyder BER, Bols ML, Rhoda HM, Plessers D, Schoonheydt RA, Sels BF, Solomon EI. Cage effects control the mechanism of methane hydroxylation in zeolites. Science 2021; 373:327-331. [PMID: 34437151 PMCID: PMC10353845 DOI: 10.1126/science.abd5803] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 03/22/2021] [Accepted: 05/10/2021] [Indexed: 11/03/2022]
Abstract
Catalytic conversion of methane to methanol remains an economically tantalizing but fundamentally challenging goal. Current technologies based on zeolites deactivate too rapidly for practical application. We found that similar active sites hosted in different zeolite lattices can exhibit markedly different reactivity with methane, depending on the size of the zeolite pore apertures. Whereas zeolite with large pore apertures deactivates completely after a single turnover, 40% of active sites in zeolite with small pore apertures are regenerated, enabling a catalytic cycle. Detailed spectroscopic characterization of reaction intermediates and density functional theory calculations show that hindered diffusion through small pore apertures disfavors premature release of CH3 radicals from the active site after C-H activation, thereby promoting radical recombination to form methanol rather than deactivated Fe-OCH3 centers elsewhere in the lattice.
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Affiliation(s)
| | - Max L Bols
- Department of Microbial and Molecular Systems, Centre for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, B-3001 Leuven, Belgium
| | - Hannah M Rhoda
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Dieter Plessers
- Department of Microbial and Molecular Systems, Centre for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, B-3001 Leuven, Belgium
| | - Robert A Schoonheydt
- Department of Microbial and Molecular Systems, Centre for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, B-3001 Leuven, Belgium.
| | - Bert F Sels
- Department of Microbial and Molecular Systems, Centre for Sustainable Catalysis and Engineering, KU Leuven-University of Leuven, B-3001 Leuven, Belgium.
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA
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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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Bols ML, Snyder BER, Rhoda HM, Cnudde P, Fayad G, Schoonheydt RA, Van Speybroeck V, Solomon EI, Sels BF. Coordination and activation of nitrous oxide by iron zeolites. Nat Catal 2021. [DOI: 10.1038/s41929-021-00602-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bols ML, Rhoda HM, Snyder BER, Solomon EI, Pierloot K, Schoonheydt RA, Sels BF. Advances in the synthesis, characterisation, and mechanistic understanding of active sites in Fe-zeolites for redox catalysts. Dalton Trans 2020; 49:14749-14757. [PMID: 33140781 DOI: 10.1039/d0dt01857k] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The recent research developments on the active sites in Fe-zeolites for redox catalysis are discussed. Building on the characterisation of the α-Fe/α-O active sites in the beta and chabazite zeolites, we demonstrate a bottom-up approach to successfully understand and develop Fe-zeolite catalysts. We use the room temperature benzene to phenol reaction as a relevant example. We then suggest how the spectroscopic identification of other monomeric and dimeric iron sites could be tackled. The challenges in the characterisation of active sites and intermediates in NOX selective catalytic reduction catalysts and further development of catalysts for mild partial methane oxidation are briefly discussed.
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Affiliation(s)
- Max L Bols
- Department of Microbial and Molecular Systems, KU Leuven, 3001 Heverlee, Belgium.
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10
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Bols ML, Hallaert SD, Snyder BER, Devos J, Plessers D, Rhoda HM, Dusselier M, Schoonheydt RA, Pierloot K, Solomon EI, Sels BF. Spectroscopic Identification of the α-Fe/α-O Active Site in Fe-CHA Zeolite for the Low-Temperature Activation of the Methane C-H Bond. J Am Chem Soc 2018; 140:12021-12032. [PMID: 30169036 DOI: 10.1021/jacs.8b05877] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The formation of single-site α-Fe in the CHA zeolite topology is demonstrated. The site is shown to be active in oxygen atom abstraction from N2O to form a highly reactive α-O, capable of methane activation at room temperature to form methanol. The methanol product can subsequently be desorbed by online steaming at 200 °C. For the intermediate steps of the reaction cycle, the evolution of the Fe active site is monitored by UV-vis-NIR and Mössbauer spectroscopy. A B3LYP-DFT model of the α-Fe site in CHA is constructed, and the ligand field transitions are calculated by CASPT2. The model is experimentally substantiated by the preferential formation of α-Fe over other Fe species, the requirement of paired framework aluminum and a MeOH/Fe ratio indicating a mononuclear active site. The simple CHA topology is shown to mitigate the heterogeneity of iron speciation found on other Fe-zeolites, with Fe2O3 being the only identifiable phase other than α-Fe formed in Fe-CHA. The α-Fe site is formed in the d6r composite building unit, which occurs frequently across synthetic and natural zeolites. Finally, through a comparison between α-Fe in Fe-CHA and Fe-*BEA, the topology's 6MR geometry is found to influence the structure, the ligand field, and consequently the spectroscopy of the α-Fe site in a predictable manner. Variations in zeolite topology can thus be used to rationally tune the active site properties.
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Affiliation(s)
- Max L Bols
- Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Simon D Hallaert
- Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Benjamin E R Snyder
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Julien Devos
- Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Dieter Plessers
- Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Hannah M Rhoda
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Michiel Dusselier
- Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Robert A Schoonheydt
- Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Kristine Pierloot
- Department of Chemistry , 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
| | - Bert F Sels
- Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
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Snyder BER, Bols ML, Schoonheydt RA, Sels BF, Solomon EI. Iron and Copper Active Sites in Zeolites and Their Correlation to Metalloenzymes. Chem Rev 2017; 118:2718-2768. [DOI: 10.1021/acs.chemrev.7b00344] [Citation(s) in RCA: 193] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Benjamin E. R. Snyder
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Max L. Bols
- Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis, KU Leuven—University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Robert A. Schoonheydt
- Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis, KU Leuven—University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Bert F. Sels
- Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis, KU Leuven—University of 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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12
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Hallaert SD, Bols ML, Vanelderen P, Schoonheydt RA, Sels BF, Pierloot K. Identification of α-Fe in High-Silica Zeolites on the Basis of ab Initio Electronic Structure Calculations. Inorg Chem 2017; 56:10681-10690. [DOI: 10.1021/acs.inorgchem.7b01653] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Simon D. Hallaert
- Department
of Chemistry and ‡Centre for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Max L. Bols
- Department
of Chemistry and ‡Centre for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Pieter Vanelderen
- Department
of Chemistry and ‡Centre for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Robert A. Schoonheydt
- Department
of Chemistry and ‡Centre for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Bert F. Sels
- Department
of Chemistry and ‡Centre for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Kristine Pierloot
- Department
of Chemistry and ‡Centre for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
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Snyder BER, Vanelderen P, Bols ML, Hallaert SD, Böttger LH, Ungur L, Pierloot K, Schoonheydt RA, Sels BF, Solomon EI. The active site of low-temperature methane hydroxylation in iron-containing zeolites. Nature 2016; 536:317-21. [PMID: 27535535 DOI: 10.1038/nature19059] [Citation(s) in RCA: 228] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 06/13/2016] [Indexed: 12/21/2022]
Abstract
An efficient catalytic process for converting methane into methanol could have far-reaching economic implications. Iron-containing zeolites (microporous aluminosilicate minerals) are noteworthy in this regard, having an outstanding ability to hydroxylate methane rapidly at room temperature to form methanol. Reactivity occurs at an extra-lattice active site called α-Fe(ii), which is activated by nitrous oxide to form the reactive intermediate α-O; however, despite nearly three decades of research, the nature of the active site and the factors determining its exceptional reactivity are unclear. The main difficulty is that the reactive species-α-Fe(ii) and α-O-are challenging to probe spectroscopically: data from bulk techniques such as X-ray absorption spectroscopy and magnetic susceptibility are complicated by contributions from inactive 'spectator' iron. Here we show that a site-selective spectroscopic method regularly used in bioinorganic chemistry can overcome this problem. Magnetic circular dichroism reveals α-Fe(ii) to be a mononuclear, high-spin, square planar Fe(ii) site, while the reactive intermediate, α-O, is a mononuclear, high-spin Fe(iv)=O species, whose exceptional reactivity derives from a constrained coordination geometry enforced by the zeolite lattice. These findings illustrate the value of our approach to exploring active sites in heterogeneous systems. The results also suggest that using matrix constraints to activate metal sites for function-producing what is known in the context of metalloenzymes as an 'entatic' state-might be a useful way to tune the activity of heterogeneous catalysts.
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Affiliation(s)
- Benjamin E R Snyder
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Pieter Vanelderen
- Department of Chemistry, Stanford University, Stanford, California 94305, USA.,Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis, KU Leuven - University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Max L Bols
- Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis, KU Leuven - University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Simon D Hallaert
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Lars H Böttger
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Liviu Ungur
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Kristine Pierloot
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Robert A Schoonheydt
- Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis, KU Leuven - University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Bert F Sels
- Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis, KU Leuven - University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, USA.,Photon Science, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
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