Direct observation of tin sites and their reversible interconversion in zeolites by solid-state NMR spectroscopy
Direct observation of tin sites and their reversible interconversion in zeolites by solid-state NMR spectroscopy
复制标题
通过固态核磁共振波谱直接观察沸石中的锡位点及其可逆相互转化
DOI：
10.1038/s42004-018-0023-1
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发表时间：
2018
影响因子：
5.9
通讯作者：
Feng Deng
中科院分区：
文献类型：
--
作者：
Guodong Qi;Qiang Wang;Jun Xu;Qinming Wu;Chao Wang;Xingling Zhao;Xiangju Meng;Fengshou Xiao;Feng Deng
金属取代沸石是一类重要的固体刘易斯酸，具有广泛的应用。尽管这种类型的催化剂很重要，但识别活性位点可能具有挑战性，因为不同类型的金属位点在沸石中经历相似的环境。本文对Sn-β沸石中不同的锡位进行了直接观察。通过一维和二维质子检测的1H/119 Sn相关固态NMR光谱将羟基与Sn原子相关联，明确地确定了两种类型的开放锡位点，其仅相当于约1.5 × 10 - 4个。占总锡含量的17%。观察到开放和封闭的锡网站之间的可逆转换。这些结果为研究Sn-β沸石中锡中心的性质提供了有价值的见解，并为使用质子检测的固态NMR方法表征沸石催化剂中的金属中心开辟了一条途径。
Metal-substituted zeolites are an important type of solid Lewis acid with a wide range of applications. Despite the importance of this type of catalyst, identifying active sites can be challenging because different types of metal sites experience similar environments in zeolites. Here we show direct observation of different tin sites in Sn-β zeolite. Two types of open tin sites are unambiguously identified via correlating the hydroxyl groups to Sn atoms with one- and two-dimensional proton-detected1H/119Sn correlation solid-state NMR spectroscopy, which only amounts to ca. 17% of the total tin content. A reversible transformation between the open and closed tin site is observed. The results provide valuable insights into the nature of tin sites in Sn-β zeolite and open an avenue for the use of proton-detected solid-state NMR methods for characterization of metal sites in zeolite catalysts.