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Tong Y, Zhang L, Ma H, Wang Y, Liu X. Understanding the Structural and Catalytic Properties of Al(IV)-2 Acidic Sites of ZSM-5. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2824. [PMID: 38930195 PMCID: PMC11204418 DOI: 10.3390/ma17122824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 06/05/2024] [Accepted: 06/05/2024] [Indexed: 06/28/2024]
Abstract
It is crucial to identify the structures of active sites to understand how catalysts function and to use that understanding to develop better catalytic materials. ZSM-5 zeolites with dominant Al(IV)-2 sites have been developed in this work. 1H-27Al 2D HMQC and 2D 1H TQ(DQ)-SQ NMR experiments have been performed to investigate the structural properties of this acidic site. The Al(IV)-2 sites have Brønsted and Lewis acid characteristics. The catalytic performance of Al(IV)-2 sites has been tested by n-dodecane cracking reactions. The catalytic results show that the Brønsted acidic strength of the Al(IV)-2 sites is comparable to that of the Al(IV)-1 sites, but the Al(IV)-2 sites' Lewis acid characteristics provide extra catalytic activity. We have gained valuable insights into the characteristics of Al(IV)-2 acid sites within these materials.
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Affiliation(s)
- Yan Tong
- School of Materials, Sun Yat-sen University, Shenzhen 518107, China; (Y.T.); (H.M.)
| | - Li Zhang
- Lanzhou Petrochemical Research Center, Petrochemical Research Institute, PetroChina, Lanzhou 730060, China; (L.Z.); (Y.W.)
| | - Hong Ma
- School of Materials, Sun Yat-sen University, Shenzhen 518107, China; (Y.T.); (H.M.)
| | - Yi Wang
- Lanzhou Petrochemical Research Center, Petrochemical Research Institute, PetroChina, Lanzhou 730060, China; (L.Z.); (Y.W.)
| | - Xiaolong Liu
- School of Materials, Sun Yat-sen University, Shenzhen 518107, China; (Y.T.); (H.M.)
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Ji Y, Chen K, Han X, Bao X, Hou G. Precise Structural and Dynamical Details in Zeolites Revealed by Coupling-Edited 1H- 17O Double Resonance NMR Spectroscopy. J Am Chem Soc 2024. [PMID: 38528765 DOI: 10.1021/jacs.3c14787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
Despite the extensive industrial and research interests in zeolites, their intrinsic catalytic nature is not fully understood due to the complexity of the hydroxyl-aluminum moieties. 17O NMR would provide irreplaceable opportunities for much-needed fine structural determination given the ubiquitous presence of oxygen atoms in nearly all species; however, the low sensitivity and quadrupolar nature of oxygen-17 make its NMR spectroscopic elucidation challenging. Here, we show that state-of-the-art double resonance solid-state NMR techniques have been combined with spectral editing methods based on scalar (through-bond) and dipolar (through-space) couplings, which allowed us to address the subtle protonic structures in zeolites. Notably, the often-neglected and undesired second-order quadrupolar-dipolar cross-term interaction ("2nd-QD interaction") can actually be exploited and can help gain invaluable information. Eventually, a comprehensive set of 1H-17O/1H-27Al double resonance NMR with J-/D-coupling spectral editing techniques have been designed in this work and enabled us to reveal atomic-scale precise structural and dynamical details in zeolites including: 1) The jump rate of the bridging acid site (BAS) proton is relatively low, i.e., far less than 100 s-1 at room temperature. 2) The Al-OH groups with 1H chemical shift at 2.6-2.8 ppm, at least for nonseverely dealuminated H-ZSM-5 catalysts, exhibit a rigid bridging environment similar to that of BAS. 3) The Si-OH groups at 2.0 ppm are not hydrogen bonded and undergo fast cone-rotational motion. The results in this study predict the 2nd-QD interaction to be universal for any rigid -17O-H environment, such as those in metal oxide surfaces or biomaterials.
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Affiliation(s)
- Yi Ji
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kuizhi Chen
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
| | - Xiuwen Han
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
| | - Xinhe Bao
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
| | - Guangjin Hou
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
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Zhan H, Liu J, Fang Q, Chen X, Hu L. Accelerated Pure Shift NMR Spectroscopy with Deep Learning. Anal Chem 2024; 96:1515-1521. [PMID: 38232235 DOI: 10.1021/acs.analchem.3c04007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Pure shift nuclear magnetic resonance (NMR) spectroscopy presents a promising solution to provide sufficient spectral resolution and has been increasingly applied in various branches of chemistry, but the optimal resolution is generally accompanied by long experimental times. We present a proof of concept of deep learning for fast, high-quality, and reliable pure shift NMR reconstruction. The deep learning (DL) protocol allows one to eliminate undersampling artifacts, distinguish peaks with close chemical shifts, and reconstruct high-resolution pure shift NMR spectroscopy along with accelerated acquisition. More meaningfully, the lightweight neural network delivers satisfactory reconstruction performance on personal computers by several hundred simulated data learning, which somewhat lifts the prohibiting demand for a large volume of real training samples and advanced computing hardware generally required in DL projects. Additionally, an M-to-S strategy applicable to common DL cases is further exploited to boost the network generalization capability. As a result, this study takes a meaningful step toward deep learning protocols for broad chemical applications.
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Affiliation(s)
- Haolin Zhan
- Department of Biomedical Engineering, Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Optoelectronics Engineering, Hefei University of Technology, Hefei 230009, China
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
| | - Jiawei Liu
- Department of Biomedical Engineering, Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Optoelectronics Engineering, Hefei University of Technology, Hefei 230009, China
| | - Qiyuan Fang
- Department of Biomedical Engineering, Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Optoelectronics Engineering, Hefei University of Technology, Hefei 230009, China
| | - Xinyu Chen
- Department of Biomedical Engineering, Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Optoelectronics Engineering, Hefei University of Technology, Hefei 230009, China
| | - Liangliang Hu
- Department of Biomedical Engineering, Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Optoelectronics Engineering, Hefei University of Technology, Hefei 230009, China
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Schmithorst MB, Prasad S, Moini A, Chmelka BF. Direct Detection of Paired Aluminum Heteroatoms in Chabazite Zeolite Catalysts and Their Significance for Methanol Dehydration Reactivity. J Am Chem Soc 2023; 145:18215-18220. [PMID: 37552830 DOI: 10.1021/jacs.3c05708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
The distributions of heteroatoms within zeolite frameworks have important influences on the locations of exchangeable cations, which account for the diverse adsorption and reaction properties of zeolite catalysts. In particular for aluminosilicate zeolites, paired configurations of aluminum atoms separated by one or two tetrahedrally coordinated silicon atoms are important for charge-balancing pairs of H+ cations, which are active for methanol dehydration, or divalent metal cations, such as Cu2+, which selectively catalyze the reduction of NOx, both technologically important reactions. Such paired heteroatom configurations, however, are challenging to detect and probe, due to the typically nonstoichiometric compositions and nonperiodic distributions of aluminum atoms within aluminosilicate zeolite frameworks. Nevertheless, distinct configurations of paired framework aluminum atoms are unambiguously detected and resolved in solid-state 2D 27Al-29Si and 29Si-29Si NMR spectra, which are sensitive to the local environments of covalently bonded 27Al-O-29Si and 29Si-O-29Si moieties, respectively. Specifically, two H+-chabazite zeolites with the same bulk framework aluminum contents are shown to have different types and populations of closely paired aluminum species, which correlate with higher activity for methanol dehydration. The methodologies and insights are expected to be broadly applicable to analyses of heteroatom sites, their distributions, and adsorption and reaction properties in other zeolite framework types.
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Affiliation(s)
- Michael B Schmithorst
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | | | - Ahmad Moini
- BASF Corporation, Iselin, New Jersey 08830, United States
| | - Bradley F Chmelka
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
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Wang Z, Xiao D, Chen K, Lou C, Liang L, Xu S, Hou G. Identity, Evolution, and Acidity of Partially Framework-Coordinated Al Species in Zeolites Probed by TMP 31P-NMR and FTIR. ACS Catal 2023. [DOI: 10.1021/acscatal.3c00714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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Chen J, Wang F, Wen Y, Tang W, Peng L. Emerging Applications of 17O Solid-State NMR Spectroscopy for Catalytic Oxides. ACS Catal 2023. [DOI: 10.1021/acscatal.2c06267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- Junchao Chen
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Fang Wang
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yujie Wen
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Weiping Tang
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Luming Peng
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
- Jiangsu Key Laboratory of Vehicle Emissions Control, Nanjing University, Nanjing 210093, China
- Frontiers Science Center for Critical Earth Material Cycling (FSC-CEMaC), Nanjing University, Nanjing, Jiangsu 210023, China
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Pham TN, Nguyen V, Nguyen-Phu H, Wang B, Crossley S. Influence of Brønsted Acid Site Proximity on Alkane Cracking in MFI Zeolites. ACS Catal 2023. [DOI: 10.1021/acscatal.2c05291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Tram N. Pham
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma73019, United States
| | - Vy Nguyen
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma73019, United States
| | - Huy Nguyen-Phu
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma73019, United States
| | - Bin Wang
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma73019, United States
| | - Steven Crossley
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma73019, United States
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