Nuclear spin relaxation as a probe of zeolite acidity: a combined NMR and TPD investigation of pyridine in HZSM-5.
Nuclear spin relaxation as a probe of zeolite acidity: a combined NMR and TPD investigation of pyridine in HZSM-5.
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核自旋弛豫作为沸石酸度的探针：HZSM-5 中吡啶的 NMR 和 TPD 联合研究。
DOI：
10.1039/d1cp01515j
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
C. D'agostino
中科院分区：
文献类型：
--
作者：
N. Robinson;P. Bräuer;A. York;C. D'agostino
利用二维核磁共振（NMR）弛豫时间测定了微孔HZSM-5分子筛中吡啶的相对表面亲和力。核自旋弛豫时间的无量纲比T1/T2对沸石的硅/氧化铝比（SAR）表现出很强的敏感性，表明了材料的酸度。这一趋势可以解释为吡啶的表面亲和力随着SAR的降低而增加。程序化解吸温度（TPD）分析证实了这一观察结果，揭示了与吸附吡啶相关的解吸热作为SAR降低的函数的明显增加。核磁共振和TPD数据之间的直接相关性表明，核磁共振弛豫时间分析可以成为微孔固体中吸附现象的非侵入性表征的有价值的工具。
The relative surface affinities of pyridine within microporous HZSM-5 zeolites are explored using two-dimensional 1H nuclear magnetic resonance (NMR) relaxation time measurements. The dimensionless ratio of longitudinal-to-transverse nuclear spin relaxation times T1/T2 is shown to exhibit strong sensitivity to the silica/alumina ratio (SAR) of these zeolites, which is indicative of material acidity. This trend is interpreted in terms of increased pyridine surface affinity with decreasing SAR. Temperature programmed desorption (TPD) analysis corroborates this observation, revealing a distinct increase in the heat of desorption associated with adsorbed pyridine as a function of decreasing SAR. A direct correlation between NMR and TPD data suggests NMR relaxation time analysis can be a valuable tool for the non-invasive characterisation of adsorption phenomena in microporous solids.
在存在场梯度的情况下测量真实的横向核磁共振弛豫。
DOI：
10.1063/1.4818806
发表时间：
2013
期刊：
The Journal of chemical physics
影响因子：
--
作者：
Mitchell J
通讯作者：
Mitchell J