Phosphatation of Zeolite H-ZSM-5: A Combined Microscopy and Spectroscopy Study

Authors

  • Hendrik E. van der Bij,

    1. Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterial Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht (The Netherlands)
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  • Dr. Luis R. Aramburo,

    1. Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterial Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht (The Netherlands)
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  • Dr. Bjørnar Arstad,

    1. Department of Process Chemistry, SINTEF, Forskningsveien 1, 0314 Oslo (Norway)
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  • Dr. James J. Dynes,

    1. Soft X-ray Spectromicroscopy, Canadian Light Source Inc. University of Saskatchewan, 101 Perimeter Road, SK S7N 0X4, Saskatoon (Canada)
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  • Dr. Jian Wang,

    1. Soft X-ray Spectromicroscopy, Canadian Light Source Inc. University of Saskatchewan, 101 Perimeter Road, SK S7N 0X4, Saskatoon (Canada)
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  • Prof. Dr. Bert M. Weckhuysen

    Corresponding author
    1. Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterial Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht (The Netherlands)
    • Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterial Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht (The Netherlands)

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  • Scanning Transmission X-ray Microscopy, Magic-angle Spinning Nuclear Magnetic Resonance Spectroscopy, and Fourier Transform Infrared Spectroscopy.

Abstract

A variety of phosphated zeolite H-ZSM-5 samples are investigated by using a combination of Fourier transfer infrared (FTIR) spectroscopy, single pulse 27Al, 29Si, 31P, 1H-31P cross polarization (CP), 27Al-31P CP, and 27Al 3Q magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy, scanning transmission X-ray microscopy (STXM) and N2 physisorption. This approach leads to insights into the physicochemical processes that take place during phosphatation. Direct phosphatation of H-ZSM-5 promotes zeolite aggregation, as phosphorus does not penetrate deep into the zeolite material and is mostly found on and close to the outer surface of the zeolite, acting as a glue. Phosphatation of pre-steamed H-ZSM-5 gives rise to the formation of a crystalline tridymite AlPO4 phase, which is found in the mesopores of dealuminated H-ZSM-5. Framework aluminum species interacting with phosphorus are not affected by hydrothermal treatment. Dealuminated H-ZSM-5, containing AlPO4, retains relatively more framework Al atoms and acid sites during hydrothermal treatment than directly phosphated H-ZSM-5.

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