TY - JOUR
T1 - Observation of Water-Induced Synergistic Acidic Site from NMR-Invisible Al in Zeolite via Solid-State NMR Spectroscopy
AU - Wang, Xingxing
AU - Wang, Qiang
AU - Wang, Chao
AU - Chu, Yueying
AU - Hu, Min
AU - Deng, Feng
AU - Yu, Jihong
AU - Xu, Jun
N1 - Publisher Copyright:
© 2025 American Chemical Society.
PY - 2025/5/28
Y1 - 2025/5/28
N2 - Zeolites are highly sensitive to water, which significantly affects their acidity─a key factor in catalytic reactions. This study investigates the dynamic interactions between water and often overlooked active sites, specifically the “NMR-invisible” aluminum species (tricoordinated framework Al─FAL and cationic extra-framework Al─EFAL) in ultrastable Y (USY) zeolite under ambient conditions. Using solid-state NMR spectroscopy combined with theoretical calculations, we demonstrate that water readily undergoes dissociative adsorption on these “NMR-invisible” Al sites. This process transforms both FAL and EFAL into “NMR-visible” Al species. The formation of new Brønsted acid sites on tetra-, penta-, and hexa-coordinated FAL results in an increase of over 60% in the BAS concentration in the USY zeolite. The hydrolysis of EFAL cations leads to the formation of Brønsted/Lewis acid synergistic sites, significantly improving the catalytic activity of USY zeolite. This enhancement is evident in the improved conversion of diethyl ether to ethene in the presence of moisture.
AB - Zeolites are highly sensitive to water, which significantly affects their acidity─a key factor in catalytic reactions. This study investigates the dynamic interactions between water and often overlooked active sites, specifically the “NMR-invisible” aluminum species (tricoordinated framework Al─FAL and cationic extra-framework Al─EFAL) in ultrastable Y (USY) zeolite under ambient conditions. Using solid-state NMR spectroscopy combined with theoretical calculations, we demonstrate that water readily undergoes dissociative adsorption on these “NMR-invisible” Al sites. This process transforms both FAL and EFAL into “NMR-visible” Al species. The formation of new Brønsted acid sites on tetra-, penta-, and hexa-coordinated FAL results in an increase of over 60% in the BAS concentration in the USY zeolite. The hydrolysis of EFAL cations leads to the formation of Brønsted/Lewis acid synergistic sites, significantly improving the catalytic activity of USY zeolite. This enhancement is evident in the improved conversion of diethyl ether to ethene in the presence of moisture.
UR - http://www.scopus.com/inward/record.url?scp=105005311049&partnerID=8YFLogxK
U2 - 10.1021/jacs.5c01756
DO - 10.1021/jacs.5c01756
M3 - Article
AN - SCOPUS:105005311049
SN - 0002-7863
VL - 147
SP - 17829
EP - 17838
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 21
ER -