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<p>The direct catalytic conversion of methane to higher aliphatic/aromatic hydrocarbons is a key challenge due to coking at high temperatures, which decreases the stability of the catalyst. This study investigates the synthesis of new Mo-modified MCM-22 catalysts for methane dehydroaromatization (MDA) reaction where the controlled dispersion of metal on aluminosilicate supports plays a crucial role. Molybdenum (Mo) was successfully incorporated into MCM-22 in various amounts (3–7 wt%) <i>via</i> thermal decomposition of prepared molybdenum precursor in a non-conventional method, and characterisation was done using XRD, FTIR, SEM, BET, NMR, NH<sub>3</sub>-TPD, H<sub>2</sub>-TPR and TEM. TEM images of the 5% Mo-loaded catalyst revealed an average particle size of 2&#xa0;nm. NH₃-TPD studies indicated the improvement of the moderate acidic character of the catalyst. Solid-state NMR studies demonstrated strong Mo-zeolite lattice interactions, where Brønsted acid sites facilitate Mo migration and anchoring through oxygen bridges to framework aluminium. Excess molybdenum incorporation leads to greater interaction with the support, leading to aluminium expulsion, forming non-framework species and Al₂(MoO₄)₃, indicating that the control molybdenum addition is essential for the host framework to retain structural integrity. Moreover, the synergistic effects between Mo and Brønsted acid sites provided superior catalytic performance at 5 wt% Mo loading (5Mo/MCM-22) with methane conversion of ~ 11.6% and benzene selectivity of ~ 87% at 700&#xa0;°C. This study highlights the significance of Mo loading on MCM-22 for improved benzene selectivity in methane dehydroaromatization reaction.</p> Graphical Abstract

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Enhancing Aromatic Selectivity via Non-conventionally Modified Mo/MCM-22 Catalyst in a Nonoxidative Methane Dehydroaromatization Reaction

  • 期刊论文

  • 发表日期：

    2025年12月13日

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  • Anil Chandra Kothari,
  • Ramkaran,
  • Sonu Bhandari,
  • Shivani Singh,
  • Prem Lama,
  • Rajaram Bal

摘要

The direct catalytic conversion of methane to higher aliphatic/aromatic hydrocarbons is a key challenge due to coking at high temperatures, which decreases the stability of the catalyst. This study investigates the synthesis of new Mo-modified MCM-22 catalysts for methane dehydroaromatization (MDA) reaction where the controlled dispersion of metal on aluminosilicate supports plays a crucial role. Molybdenum (Mo) was successfully incorporated into MCM-22 in various amounts (3–7 wt%) via thermal decomposition of prepared molybdenum precursor in a non-conventional method, and characterisation was done using XRD, FTIR, SEM, BET, NMR, NH3-TPD, H2-TPR and TEM. TEM images of the 5% Mo-loaded catalyst revealed an average particle size of 2 nm. NH₃-TPD studies indicated the improvement of the moderate acidic character of the catalyst. Solid-state NMR studies demonstrated strong Mo-zeolite lattice interactions, where Brønsted acid sites facilitate Mo migration and anchoring through oxygen bridges to framework aluminium. Excess molybdenum incorporation leads to greater interaction with the support, leading to aluminium expulsion, forming non-framework species and Al₂(MoO₄)₃, indicating that the control molybdenum addition is essential for the host framework to retain structural integrity. Moreover, the synergistic effects between Mo and Brønsted acid sites provided superior catalytic performance at 5 wt% Mo loading (5Mo/MCM-22) with methane conversion of ~ 11.6% and benzene selectivity of ~ 87% at 700 °C. This study highlights the significance of Mo loading on MCM-22 for improved benzene selectivity in methane dehydroaromatization reaction.

Graphical Abstract