Synergic Effect of Active Sites in Zinc-Modified ZSM-5 Zeolites as Revealed by High-Field Solid-State NMR Spectroscopy
Synergic Effect of Active Sites in Zinc-Modified ZSM-5 Zeolites as Revealed by High-Field Solid-State NMR Spectroscopy
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高场固态核磁共振波谱揭示锌改性 ZSM-5 沸石活性位点的协同效应
DOI：
10.1002/anie.201608322
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发表时间：
2016-12-19
影响因子：
16.6
通讯作者：
Deng, Feng
中科院分区：
文献类型：
--
作者：
Qi, Guodong;Wang, Qiang;Deng, Feng
了解金属负载催化剂中活性中心的性质对于建立其结构-性能关系具有重要意义。金属负载型催化剂的优异催化性能通常归因于不同活性中心的协同效应，然而这并没有很好的光谱表征。本文报道了用高场固体核磁共振谱直接检测Zn改性ZSM-5分子筛表面Zn物种和Zn ~（2+）与B酸中心之间的H-1-Zn-67核间相互作用。所观察到的促进甲烷的C-H键活化是合理的增强的布朗斯台德酸性所产生的协同效应从空间的接近/相互作用之间的Zn 2+离子和布朗斯台德酸性质子。通过H-1-Zn-67双共振固体核磁共振谱确定了协同活性中心的浓度。
Understanding the nature of active sites in metal-supported 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 H-1-Zn-67 internuclear interaction between Zn2+ ions and BrOnsted 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 BrOnsted acidity generated by synergic effects arising from the spatial proximity/interaction between Zn2+ ions and BrOnsted acidic protons. The concentration of synergic active sites is determined by H-1-Zn-67 double-resonance solid-state NMR spectroscopy.