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Lu J, Aydin C, Browning ND, Gates BC. Rücktitelbild: Imaging Isolated Gold Atom Catalytic Sites in Zeolite NaY (Angew. Chem. 24/2012). Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201202061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Lu J, Aydin C, Browning ND, Gates BC. Back Cover: Imaging Isolated Gold Atom Catalytic Sites in Zeolite NaY (Angew. Chem. Int. Ed. 24/2012). Angew Chem Int Ed Engl 2012. [DOI: 10.1002/anie.201202061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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128
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Lu J, Aydin C, Liang AJ, Chen CY, Browning ND, Gates BC. Site-Isolated Molecular Iridium Complex Catalyst Supported in the 1-Dimensional Channels of Zeolite HSSZ-53: Characterization by Spectroscopy and Aberration-Corrected Scanning Transmission Electron Microscopy. ACS Catal 2012. [DOI: 10.1021/cs300139p] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Abstract
Our aim in this review is to assess key recent findings that point to atomically dispersed noble metals as catalytic sites on solid supports, which may be viewed as ligands bonded to the metal. Both zeolites and open metal oxide supports are considered; the former offer the advantages of uniform, crystalline structures to facilitate fundamental understanding, and the latter offer numerous advantages in applications. The notion of strong interactions between metals and supports has resurfaced in the recent literature to explain how subnanometer clusters and even atoms of noble metals such as platinum and gold survive under often harsh reaction conditions on some supports, such as ceria and perovskites. Individual cations of platinum, palladium, rhodium, or other metals anchored to supports through M-O bonds can be formed on these supports in configurations that are stable and catalytically active for several reactions illustrated here, notably, oxidation and reduction. The development of effective synthesis methods and the identification of suitable stabilizers and promoters are expected to lead to the increasing application of atomically dispersed noble metal catalysts for practical processes characterized by efficient resource utilization and cost savings.
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Aydin C, Lu J, Browning ND, Gates BC. A "smart" catalyst: sinter-resistant supported iridium clusters visualized with electron microscopy. Angew Chem Int Ed Engl 2012; 51:5929-34. [PMID: 22517504 DOI: 10.1002/anie.201201726] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Indexed: 11/06/2022]
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Aydin C, Lu J, Browning ND, Gates BC. A “Smart” Catalyst: Sinter-Resistant Supported Iridium Clusters Visualized with Electron Microscopy. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201201726] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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132
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Runnebaum RC, Nimmanwudipong T, Doan J, Block DE, Gates BC. Catalytic Conversion of Furan to Gasoline-Range Aliphatic Hydrocarbons via Ring Opening and Decarbonylation Reactions Catalyzed by Pt/γ-Al2O3. Catal Letters 2012. [DOI: 10.1007/s10562-012-0816-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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133
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Lu J, Aydin C, Browning ND, Gates BC. Hydrogen activation and metal hydride formation trigger cluster formation from supported iridium complexes. J Am Chem Soc 2012; 134:5022-5. [PMID: 22397595 DOI: 10.1021/ja211380p] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The formation of iridium clusters from supported mononuclear iridium complexes in H(2) at 300 K and 1 bar was investigated by spectroscopy and atomic-resolution scanning transmission electron microscopy. The first steps of cluster formation from zeolite-supported Ir(C(2)H(4))(2) complexes are triggered by the activation of H(2) and the formation of iridium hydride, accompanied by the breaking of iridium-support bonds. This reactivity can be controlled by the choice of ligands on the iridium, which include the support.
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Lu J, Aydin C, Browning ND, Gates BC. Imaging Isolated Gold Atom Catalytic Sites in Zeolite NaY. Angew Chem Int Ed Engl 2012; 51:5842-6. [DOI: 10.1002/anie.201107391] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Indexed: 11/07/2022]
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135
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Lu J, Aydin C, Browning ND, Gates BC. Imaging Isolated Gold Atom Catalytic Sites in Zeolite NaY. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201107391] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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136
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Runnebaum RC, Nimmanwudipong T, Block DE, Gates BC. Catalytic conversion of compounds representative of lignin-derived bio-oils: a reaction network for guaiacol, anisole, 4-methylanisole, and cyclohexanone conversion catalysed by Pt/γ-Al2O3. Catal Sci Technol 2012. [DOI: 10.1039/c1cy00169h] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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137
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Aydin C, Lu J, Liang AJ, Chen CY, Browning ND, Gates BC. Tracking iridium atoms with electron microscopy: first steps of metal nanocluster formation in one-dimensional zeolite channels. NANO LETTERS 2011; 11:5537-5541. [PMID: 22088173 DOI: 10.1021/nl2034305] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Using aberration-corrected scanning transmission electron microscopy (STEM), we imaged iridium atoms in isolated iridium complexes in the one-dimensional nonintersecting 14-ring channels of zeolite SSZ-53. STEM allows tracking of the movement of atoms in the channels, demonstrating the interaction of iridium with the zeolite framework (channel confinement) and providing a direct visualization of the initial steps of metal nanocluster formation. The results demonstrate how STEM can be used to help design improved catalysts by identifying the catalytic sites and observing how they change in reactive atmospheres.
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Aydin C, Lu J, Shirai M, Browning ND, Gates BC. Ir6 Clusters Compartmentalized in the Supercages of Zeolite NaY: Direct Imaging of a Catalyst with Aberration-Corrected Scanning Transmission Electron Microscopy. ACS Catal 2011. [DOI: 10.1021/cs2004104] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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139
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Lu J, Serna P, Gates BC. Zeolite- and MgO-Supported Molecular Iridium Complexes: Support and Ligand Effects in Catalysis of Ethene Hydrogenation and H–D Exchange in the Conversion of H2 + D2. ACS Catal 2011. [DOI: 10.1021/cs200397r] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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140
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Lu J, Serna P, Aydin C, Browning ND, Gates BC. Supported Molecular Iridium Catalysts: Resolving Effects of Metal Nuclearity and Supports as Ligands. J Am Chem Soc 2011; 133:16186-95. [DOI: 10.1021/ja206486j] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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141
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Serna P, Gates BC. Zeolite-supported rhodium complexes and clusters: switching catalytic selectivity by controlling structures of essentially molecular species. J Am Chem Soc 2011; 133:4714-7. [PMID: 21391590 DOI: 10.1021/ja111749s] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Precise synthesis and characterization of site-isolated rhodium complexes and extremely small rhodium clusters supported on zeolite HY allow control of the catalyst selectivity in the conversion of ethene to n-butene or ethane, respectively, as a result of tuning the structure of the active sites at a molecular level.
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Runnebaum RC, Nimmanwudipong T, Block DE, Gates BC. Catalytic Conversion of Anisole: Evidence of Oxygen Removal in Reactions with Hydrogen. Catal Letters 2010. [DOI: 10.1007/s10562-010-0510-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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143
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Ortalan V, Uzun A, Gates BC, Browning ND. Towards full-structure determination of bimetallic nanoparticles with an aberration-corrected electron microscope. NATURE NANOTECHNOLOGY 2010; 5:843-847. [PMID: 21102466 DOI: 10.1038/nnano.2010.234] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Accepted: 10/29/2010] [Indexed: 05/30/2023]
Abstract
To fully understand the properties of functional nanostructures such as catalytic nanoclusters, it is necessary to know the positions of all the atoms in the nanostructure. The catalytic properties of metal nanoclusters can often be improved by the addition of a second metal, but little is known about the role of the different metals in these bimetallic catalysts, or about their interactions with each other and the support material. Here we show that aberration-corrected scanning transmission electron microscopy of supported rhodium-iridium clusters, combined with dynamic multislice image simulations, can identify individual atoms, map the full structure, and determine changes in the positions of metal atoms in sequential images. This approach could help in the development of new and improved catalysts and other functional nanostructures.
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Kulkarni A, Chi M, Ortalan V, Browning ND, Gates BC. Atomic Resolution of the Structure of a Metal-Support Interface: Triosmium Clusters on MgO(110). Angew Chem Int Ed Engl 2010; 49:10089-92. [DOI: 10.1002/anie.201005105] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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145
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Kulkarni A, Chi M, Ortalan V, Browning ND, Gates BC. Atomic Resolution of the Structure of a Metal-Support Interface: Triosmium Clusters on MgO(110). Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201005105] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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146
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Mehraeen S, Kulkarni A, Chi M, Reed BW, Okamoto NL, Browning ND, Gates BC. Triosmium Clusters on a Support: Determination of Structure by X-ray Absorption Spectroscopy and High-Resolution Microscopy. Chemistry 2010; 17:1000-8. [DOI: 10.1002/chem.201000860] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Indexed: 11/08/2022]
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147
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Lobo-Lapidus RJ, Gates BC. Supported rhenium complexes: almost uniform rhenium tricarbonyls synthesized from CH3Re(CO)5 and HY zeolite. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:16368-16374. [PMID: 20560580 DOI: 10.1021/la101344t] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Supported rhenium complexes were prepared from CH(3)Re(CO)(5) and dealuminated HY zeolite or NaY zeolite, each with a Si/Al atomic ratio of 30. The samples were characterized with infrared (IR) and extended X-ray absorption fine structure (EXAFS) spectroscopies. EXAFS data characterizing the sample formed by the reaction of CH(3)Re(CO)(5) with dealuminated HY zeolite show that the rhenium complexes were bonded to the zeolite frame, incorporating, on average, three carbonyl ligands per Re atom (as shown by Re-C and multiple-scattering Re-O EXAFS contributions). The IR spectra, consistent with this result, show that the supported rhenium carbonyls were bonded near aluminum sites of the zeolite, as shown by the decrease in intensity of the IR bands characterizing the acidic silanol groups resulting from the reaction of the rhenium carbonyl with the zeolite. This supported metal complex was characterized by narrow peaks in the ν(CO) region of the IR spectrum, indicating highly uniform species. In contrast, the species formed from CH(3)Re(CO)(5) on NaY zeolite lost fewer carbonyl ligands than those formed on HY zeolite and were significantly less uniform, as indicated by the greater breadth of the ν(CO) bands in the IR spectra. The results show the importance of zeolite H(+) sites for the formation of uniform supported rhenium carbonyls from CH(3)Re(CO)(5); the formation of such uniform complexes did not occur on the NaY zeolite.
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149
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Lobo-Lapidus RJ, Gates BC. Probing Surface Sites of TiO2: Reactions with [HRe(CO)5] and [CH3Re(CO)5]. Chemistry 2010; 16:11386-98. [DOI: 10.1002/chem.201000267] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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150
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Ortalan V, Uzun A, Gates BC, Browning ND. Direct imaging of single metal atoms and clusters in the pores of dealuminated HY zeolite. NATURE NANOTECHNOLOGY 2010; 5:506-10. [PMID: 20495553 DOI: 10.1038/nnano.2010.92] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Accepted: 04/09/2010] [Indexed: 05/21/2023]
Abstract
Zeolites are aluminosilicate materials that contain regular three-dimensional arrays of molecular-scale pores, and they can act as hosts for catalytically active metal clusters. The catalytic properties of such zeolites depend on the sizes and shapes of the clusters, and also on the location of the clusters within the pores. Transmission electron microscopy has been used to image single atoms and nanoclusters on surfaces, but the damage caused by the electron beam has made it difficult to image zeolites. Here, we show that aberration-corrected scanning transmission electron microscopy can be used to determine the locations of individual metal atoms and nanoclusters within the pores of a zeolite. We imaged the active sites of iridium catalysts anchored in dealuminated HY zeolite crystals, determined their locations and approximate distance from the crystal surface, and deduced a possible cluster formation mechanism.
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