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Synergic Effect of Active Sites in Zinc-Modified ZSM-5 Zeolites as Revealed by High-Field Solid-State NMR Spectroscopy

Release time:2017-4-7      Source:admin      Reads:517
 
 
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     Understanding the nature of active sites in metalsupported catalysts is of great importance towards establishing their structure–property relationships. The outstanding catalytic performance of metal-supported catalysts is frequently ascribed to the synergic effect of different active sites, which is however not well spectroscopically characterized. Herein, we report the direct detection of surface Zn species and 1H–67Zn internuclear interaction between Zn2+ ions and Brønsted acid sites on Zn-modified ZSM-5 zeolites by high-field solid-state NMR spectroscopy. The observed promotion of C-H bond activation of methane is rationalized by the enhanced Brønsted acidity generated by synergic effects arising from the spatial proximity/interaction between Zn2+ ions and Brønsted acidic protons. The concentration of synergic active sites is  etermined by 1H–67Zn double-resonance solid-state NMR spectroscopy.
 
 
 
 
 
 
 
 
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