Assessing the effects of dealumination and bifunctionalization on 8-membered ring zeolite/zeo-type materials in the methanol-to-olefin catalytic process†

Abstract

C₂–C₄ shorter olefins, particularly ethylene and propylene, are crucial building blocks in modern petrochemical, polymer, and chemical industries. However, their predominant sourcing from fossil resources raises concerns due to increased awareness of carbon emissions and diminishing petroleum reserves. Therefore, a necessary shift towards sustainable resources is underway. The zeolite-catalyzed methanol-to-olefin (MTO) process, particularly over 8-MR zeolite/zeo-type materials, has gained industrial prominence in this context. If methanol strictly originated from renewable sources, then the MTO process would actively promote the “methanol economy”. Despite the advantages of zeolite/zeo-type materials, they encounter deactivation due to the accumulation of coke precursors, limiting their lifetime. While achieving high olefin selectivity in the MTO process is not challenging, improving the catalytic lifetime without compromising preferential olefin selectivity is crucial. To achieve this objective, various surface modification approaches, such as dealumination through acid etching, steaming, and constructing bifunctional catalytic systems, are applied to numerous 8-MR zeolite/zeo-type materials, including industrially operational MTO catalysts. Combining catalytic studies with advanced characterization methods, including under operando conditions, has enhanced MTO process efficiency by mitigating the formation of coke precursors. Ultimately, this study contributes to a deeper understanding of zeolite-catalyzed MTO processes, paving the way for more efficient and sustainable production of low-carbon olefins.