Advanced search
1 file | 1.77 MB

Identification of intermediates in zeolite-catalyzed reactions by in situ UV/Vis microspectroscopy and a complementary set of molecular simulations

(2013) CHEMISTRY-A EUROPEAN JOURNAL. 19(49). p.16595-16606
Author
Organization
Abstract
The optical absorption properties of (poly)aromatic hydrocarbons occluded in a nanoporous environment were investigated by theoretical and experimental methods. The carbonaceous species are an essential part of a working catalyst for the methanol-to-olefins (MTO) process. In situ UV/Vis microscopy measurements on methanol conversion over the acidic solid catalysts H-SAPO-34 and H-SSZ-13 revealed the growth of various broad absorption bands around 400, 480, and 580nm. The cationic nature of the involved species was determined by interaction of ammonia with the methanol-treated samples. To determine which organic species contribute to the various bands, a systematic series of aromatics was analyzed by means of time-dependent density functional theory (TDDFT) calculations. Static gas-phase simulations revealed the influence of structurally different hydrocarbons on the absorption spectra, whereas the influence of the zeolitic framework was examined by using supramolecular models within a quantum mechanics/molecular mechanics framework. To fully understand the origin of the main absorption peaks, a molecular dynamics (MD) study on the organic species trapped in the inorganic host was essential. During such simulation the flexibility is fully taken into account and the effect on the UV/Vis spectra is determined by performing TDDFT calculations on various snapshots of the MD run. This procedure allows an energy absorption scale to be provided and the various absorption bands determined from in situ UV/Vis spectra to be assigned to structurally different species.
Keywords
heterogeneous catalysis, density functional calculations, TO-OLEFIN CONVERSION, Vis spectroscopy, ELASTIC BAND METHOD, BRONSTED ACID SITES, UV, COKE FORMATION, REACTION-MECHANISM, EXCITED-STATES, POLYCYCLIC AROMATIC-HYDROCARBONS, DYNAMIC POLARIZABILITIES, SPACE GAUSSIAN PSEUDOPOTENTIALS, molecular dynamics, DENSITY-FUNCTIONAL THEORY, zeolites

Downloads

  • (...).pdf
    • full text
    • |
    • UGent only
    • |
    • PDF
    • |
    • 1.77 MB

Citation

Please use this url to cite or link to this publication:

Chicago
Hemelsoet, Karen, Qingyun Qian, Thierry De Meyer, Kristof De Wispelaere, Bart De Sterck, Bert M Weckhuysen, Michel Waroquier, and Veronique Van Speybroeck. 2013. “Identification of Intermediates in Zeolite-catalyzed Reactions by in Situ UV/Vis Microspectroscopy and a Complementary Set of Molecular Simulations.” Chemistry-a European Journal 19 (49): 16595–16606.
APA
Hemelsoet, Karen, Qian, Q., De Meyer, T., De Wispelaere, K., De Sterck, B., Weckhuysen, B. M., Waroquier, M., et al. (2013). Identification of intermediates in zeolite-catalyzed reactions by in situ UV/Vis microspectroscopy and a complementary set of molecular simulations. CHEMISTRY-A EUROPEAN JOURNAL, 19(49), 16595–16606.
Vancouver
1.
Hemelsoet K, Qian Q, De Meyer T, De Wispelaere K, De Sterck B, Weckhuysen BM, et al. Identification of intermediates in zeolite-catalyzed reactions by in situ UV/Vis microspectroscopy and a complementary set of molecular simulations. CHEMISTRY-A EUROPEAN JOURNAL. 2013;19(49):16595–606.
MLA
Hemelsoet, Karen, Qingyun Qian, Thierry De Meyer, et al. “Identification of Intermediates in Zeolite-catalyzed Reactions by in Situ UV/Vis Microspectroscopy and a Complementary Set of Molecular Simulations.” CHEMISTRY-A EUROPEAN JOURNAL 19.49 (2013): 16595–16606. Print.
@article{4227465,
  abstract     = {The optical absorption properties of (poly)aromatic hydrocarbons occluded in a nanoporous environment were investigated by theoretical and experimental methods. The carbonaceous species are an essential part of a working catalyst for the methanol-to-olefins (MTO) process. In situ UV/Vis microscopy measurements on methanol conversion over the acidic solid catalysts H-SAPO-34 and H-SSZ-13 revealed the growth of various broad absorption bands around 400, 480, and 580nm. The cationic nature of the involved species was determined by interaction of ammonia with the methanol-treated samples. To determine which organic species contribute to the various bands, a systematic series of aromatics was analyzed by means of time-dependent density functional theory (TDDFT) calculations. Static gas-phase simulations revealed the influence of structurally different hydrocarbons on the absorption spectra, whereas the influence of the zeolitic framework was examined by using supramolecular models within a quantum mechanics/molecular mechanics framework. To fully understand the origin of the main absorption peaks, a molecular dynamics (MD) study on the organic species trapped in the inorganic host was essential. During such simulation the flexibility is fully taken into account and the effect on the UV/Vis spectra is determined by performing TDDFT calculations on various snapshots of the MD run. This procedure allows an energy absorption scale to be provided and the various absorption bands determined from in situ UV/Vis spectra to be assigned to structurally different species.},
  author       = {Hemelsoet, Karen and Qian, Qingyun and De Meyer, Thierry and De Wispelaere, Kristof and De Sterck, Bart and Weckhuysen, Bert M and Waroquier, Michel and Van Speybroeck, Veronique},
  issn         = {0947-6539},
  journal      = {CHEMISTRY-A EUROPEAN JOURNAL},
  language     = {eng},
  number       = {49},
  pages        = {16595--16606},
  title        = {Identification of intermediates in zeolite-catalyzed reactions by in situ UV/Vis microspectroscopy and a complementary set of molecular simulations},
  url          = {http://dx.doi.org/10.1002/chem.201301965},
  volume       = {19},
  year         = {2013},
}

Altmetric
View in Altmetric
Web of Science
Times cited: