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Controlling the selectivity–stability tradeoff in zeolite catalysis: oligomerization–alkylation, cracking, and methanol-to-hydrocarbons 


    Problem Statement

    Olefins and aromatics are commodity chemicals used in producing plastics (in the petrochemical industry), lubricants, plasticizers, and surfactants, among other products. However, there is an imbalance between their production and demand, which reactions like oligomerization, alkylation, and cracking over zeolites could help address. At the same time, zeolites serve as excellent catalysts for converting methanol to hydrocarbons (MTH), olefins (MTO), or aromatics (MTA). These processes aim to produce light hydrocarbons such as propylene or to convert ethylene into higher-value alpha-olefins, aromatic hydrocarbons (BTX), and jet fuel.


    Our focus in this project is to synthesize, modify, and develop new catalysts with engineered porosity at multiple scales: from hierarchical and hollow zeolites to catalytic particles, bodies, or technical catalysts intended for implementation. Additionally, we incorporate various metals (e.g., Ni, Cr, Zn) to influence the selectivity toward the desired products.

    We utilize various reactors, including forced dynamic, operando, high-throughput packed-bed, and batch reactors.

    OLG-O2H

    Goals

    • Control the catalyst structure to balance selectivity and stability.
    • Metal modulation: Use Ni, Cr, Zn to bias reaction pathways and improve selectivity to target hydrocarbons.
    • Deactivation control: Reduce coke formation and extend catalyst lifetime with regeneration strategies.
    • Reactor optimization: Shape catalysts into bodies/extrudates and validate 100 h continuous stable operation.

    Related People

    Faseeh Kulangara Kandiyil
    Hend Omar Mohamed
    Kiruthika Jayaseelan

    Related Publications

    Gd–Modified Zn/ZSM-5 Catalysts With Suppressed Coke Formation for Methanol-to-Aromatics Conversion

    by Jayaseelan, Mohamed, Trueba, Velisoju, Morlanes, Genovese, Hedhili, Telalovic, Emwas, Castaño
    ChemCatChem Year: 2026 DOI: https://doi.org/10.1002/cctc.202501499

    Abstract

    The conversion of methanol into aromatic hydrocarbons is fundamentally constrained by the competing formation of valuable aromatic products and polyaromatic coke, which rapidly deactivates zeolite catalysts. Here, we demonstrate that cooperative modification of ZSM-5 with a bimetallic system, zinc (Zn) and gadolinium (Gd), provides an effective strategy to overcome this limitation. Structural analyses using atomic-resolution electron microscopy, X-ray diffraction, X-ray fluorescence, and solid-state 27Al nuclear magnetic resonance confirm that both metals remain atomically dispersed on the external surfaces without altering the MFI framework. Acidity measurements show that Zn introduces dehydrogenation-active Lewisacid sites, while Gd moderates strong Brønsted acid sites. Operando ultraviolet–visible spectroscopy and multi-modal coke characterization reveal that Gd suppresses polyaromatic growth, whereas Zn enhances aromatic-ring formation. Their combination yields high aromatic productivity, minimal coke deposition, and exceptional operational stability for over 72 h. The bimetallic catalyst also demonstrates excellent regeneration capability over three consecutive cycles, establishing a robust metal–acid design strategy for durable methanol-to-aromatics conversion.

    Keywords

    O2H HCE