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