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High-impact promotional effect of mo impregnation on aluminum-rich and Alkali-treated hierarchical zeolite catalysts on methanol aromatization

Ghanbari, B ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1021/acsomega.9b04407
  3. Publisher: American Chemical Society , 2020
  4. Abstract:
  5. A systematic change of HZSM-5 (HZ5) as a catalyst of the methanol to aromatics (MTA) reaction was undertaken by employing a fixed-bed tubular-type reactor under ambient pressure, applying a weight hourly space velocity (WHSV) of 2 h-1 at 375 °C, as the first report on the application of low-Si/Al-ratio alkaline-[Mo,Na]-HZSM-5 in the MTA process. To characterize the surface and textural properties of the catalysts, powder X-ray diffraction (PXRD), nitrogen adsorption/desorption, temperature-programmed desorption of ammonia (NH3-TPD), pyridine-infrared spectroscopy (Py-IR), thermogravimetric analysis (TGA), and energy-dispersive X-ray (EDX) methods were employed. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) measurements demonstrated a selectivity of up to 86 wt % (65.7 wt % for benzene, toluene, and xylene (BTX)) over 2[Mo]HZ5. NH3-TPD and Py-IR results indicated a sensible decrease of strong acid sites on the impregnated samples, while the surface analyses revealed the highest Lewis acid sites (LAS) together with the largest mesopore surface area for 2[Mo]alk-HZ5, supporting the migration of Mo species to the bulk of the catalysts. Mo impregnation had a minor effect on the observed coke formation in the promoted catalyst. Copyright © 2020 American Chemical Society
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  8. Source: ACS Omega ; Volume 5, Issue 21 , 2020 , Pages 11971-11986
  9. URL: https://pubs.acs.org/doi/10.1021/acsomega.9b04407