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Direct Ink Writing of Metal Oxide/H-ZSM-5 Catalysts for N-Hexane Cracking: A New Method of Additive Manufacturing with High Metal Oxide Loading
ACS Applied Materials and Interfaces
  • Shane Lawson
  • Alireza Farsad
  • Fateme Rezaei, Missouri University of Science and Technology
  • Douglas K. Ludlow, Missouri University of Science and Technology
  • Ali A. Rownaghi, Missouri University of Science and Technology
Abstract

Previously, 3D printing of porous materials and metal oxides was limited to low loading metal loadings, as increasing the nitrate salt concentrations, which are used to generate the oxide component, gave rise to poor rheological properties beyond 10 wt %. In this study, we addressed this problem by directly printing insoluble oxides alongside H-ZSM-5 zeolite, which allowed for increased oxide loadings. Various metal oxides such as V2O5, ZrO2, Cr2O3, and Ga2O3 were doped onto H-ZSM-5 through the additive manufacturing method. Characterization and correlation between the X-ray diffraction, NH3temperature-programmed desorption O -temperature programmed oxidation, temperature-programmed reduction, scanning electron microscopy−energy dispersive spectroscopy, and in situ CO2 DRIFTS experiments revealed that directly 3D printing metal oxides/H-ZSM-5 inks leads to significant modification in the surface properties and oxide bulk dispersion, thereby enhancing the composites’ reducibility and giving rise to widely differing product distributions in n-hexane cracking reaction. The obtained metal oxide/zeolite structured materials were used as bifunctional structured catalysts for the selective formation of light olefins from hexane at 550-600 °C and GHSV = 9000 mL/gcatalst·h in a packed-bed reactor. Among the various compositions of metal oxides/H-ZSM-5 examined (i.e., 15 wt % Ga2O3, 15 wt % ZrO2, 15 wt % V2O5, 15 wt % Cr2O3, or 5 wt % Cr/10 wt % ZrO2/10 wt % V2O5/10 wt % Ga2O3 balanced with H-ZSM-5), the 15 wt % Cr/ ZSM-5 monolith displayed the best n-hexane cracking performance, as it achieved 80-85% conversion of hexane with a 40% selectivity toward propylene, 30% selectivity toward ethylene, and 10% selectivity toward butene at 550 °C. The sample also showed zero benzene/toluene/xylene selectivity and no deactivation after 6 h. This study represents a proof-of-concept for tailoring customizable heterogeneous structured catalysts by directly 3D printing high loading of metal oxides/porous zeolite and is a breakthrough in material science.

Department(s)
Chemical and Biochemical Engineering
Comments
The involvement of S.L. in this work was sponsored by the National Science Foundation internship program (NSF CBET-1802049).
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2021 American Chemical Society (ACS), All rights reserved.
Publication Date
1-13-2021
Publication Date
13 Jan 2021
Disciplines
Citation Information
Shane Lawson, Alireza Farsad, Fateme Rezaei, Douglas K. Ludlow, et al.. "Direct Ink Writing of Metal Oxide/H-ZSM-5 Catalysts for N-Hexane Cracking: A New Method of Additive Manufacturing with High Metal Oxide Loading" ACS Applied Materials and Interfaces (2021) ISSN: 1944-8244; 1944-8252
Available at: http://works.bepress.com/douglas-ludlow/17/