Embryonic zeolites for highly efficient synthesis of dimethyl ether from syngas

• Published in: Microporous and mesoporous materials Vol. 322; p. 111138
• Main Authors: Palčić, Ana, Jaén, Sara Navarro, Wu, Dan, Cai, Mengdie, Liu, Chong, Pidko, Evgeny A., Khodakov, Andrei Y., Ordomsky, Vitaly, Valtchev, Valentin
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.07.2021; Elsevier
• Subjects: Acid sites; Chemical Sciences; DME synthesis; Embryonic zeolite; Material chemistry; Syngas; Embryonic zeolite; Acid sites; DME synthesis; Syngas
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2021.111138

Embryonic X-ray amorphous semi-formed MFI-type zeolite units mixed with the Cu–Zn–Al catalyst have been used for the direct synthesis of dimethyl ether (DME) from syngas. The hybrid catalyst with embryonic zeolite (EZ) with the particle size of 5 nm has demonstrated superior performance in terms of activity, selectivity, and stability compared to the crystalline ZSM-5 zeolite counterpart and the amorphous aluminosilicate material. The FTIR pyridine adsorption uncovered several types of active sites in EZ, including Brønsted acid sites of medium strength. The DFT modeling pointed out the key role of defect sites leading to lower strength of the acid sites in the embryonic MFI zeolite in comparison with the fully crystalline material. The effect of embryonic zeolite on the DME synthesis has been assigned to enhanced transport of methanol from Cu to ultra-small zeolite precursor units with moderate acidity, hence promoting the efficient dehydration to DME with high selectivity and stability. [Display omitted] •Embryonic zeolite with X-ray amorphous semi-formed MFI units have been synthesized.•It has been mixed with Cu–Zn–Al catalyst for direct DME synthesis from syngas.•Material demonstrated superior performance in activity, selectivity and stability.•Ultra-small zeolite precursor units with medium acidity provide efficient dehydration to DME.