JACS - 95Mo NMR of metal sites in zeolites

J. Am. Chem. Soc., 130 (12), 3722 -3723, 2008.

10.1021/ja7110916

Direct Observation of the Active Center for Methane Dehydroaromatization Using an Ultrahigh Field ⁹⁵Mo NMR Spectroscopy

Heng Zheng, Ding Ma, Xinhe Bao,* Jian Zhi Hu, Ja Hun Kwak, Yong Wang, and Charles H. F. Peden

State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R. China, and Pacific Northwest National Laboratory, P. O. Box 999, MS K8-98, Richland, Washington 99352

xhbao@dicp.ac.cn

Received December 14, 2007

Abstract:

The use of an ultrahigh magnetic field spectrometer and ⁹⁵Mo isotope enrichment facilitate the direct observation of the local structure of Mo species on Mo/zeolite catalysts by ⁹⁵Mo NMR. Top trace: The experimental ⁹⁵Mo NMR spectrum of 6Mo/HZSM-5. Bottom traces: The simulated overall spectrum (orange), the spectral component corresponding to MoO₃ (purple), and the component corresponding to the exchanged Mo species (green). The exchanged Mo species proved to be the active center for the methane dehydroaromatization (MDA) reaction.