Propane dehydrogenation catalyzed by single Lewis acid site in Sn-Beta zeolite
Propane dehydrogenation catalyzed by single Lewis acid site in Sn-Beta zeolite
复制标题
Sn-Beta 沸石单路易斯酸位催化丙烷脱氢
DOI：
10.1016/j.jcat.2020.12.019
复制
发表时间：
2021-03
影响因子：
7.3
通讯作者：
Zhu Haibo
中科院分区：
文献类型：
--
作者：
Yue Yuanyuan;Fu Jing;Wang Chuanming;Yuan Pei;Bao Xiaojun;Xie Zailai;Basset Jean-Marie;Zhu Haibo
由于丙烯下游产品的大量消耗，丙烯供需之间的差距越来越明显。丙烷脱氢（PDH）是生产丙烯的重要替代方法，因此开发环保型和经济型的催化剂已受到广泛关注。在此，我们发现具有刘易斯酸中心的Sn-β沸石可以活化C-H键，并在PDH中表现出高的催化性能。XRD、STEM和XPS表征证实了Sn物种被引入到沸石骨架中，并且H2-TPR表明Sn物种与沸石骨架之间存在强烈的相互作用。发现刘易斯酸是脱氢反应的活性中心，而布朗斯特酸是裂解反应的活性中心。脱氢速率/裂解速率与L/B比成正比，高的L/B比有利于丙烷脱氢反应。具有最高量的刘易斯酸但最低的布朗斯特/刘易斯比的Na-Sn-Beta-30催化剂在PDH中表现出最好的性能，其提供40%的丙烷转化率和92%的丙烯选择性。最重要的是，这些Sn-β沸石在苛刻的反应条件下72 h都非常稳定，没有任何可检测到的失活。密度泛函理论计算表明，锡和相邻的O原子或OH基团协同作用作为活性中心。PDH通过直接反应机制发生，其中氢分子是通过初级C3 H7基序的H原子与封闭位点的Brønsted质子或开放位点的水的质子直接偶联产生的。开放中心的反应活性高于封闭中心，根据羟基化程度的不同，计算出的本征焓垒为242 ~ 301 kJ/mol。这些高效的Sn-β分子筛为开发新一代高稳定性的PDH催化剂提供了新的可能性。
The gap between supply and demand of propylene has become more and more evident, because of a large consumption of the downstream products derived from propylene. Propane dehydrogenation (PDH) constitutes an important alternative for the production of propylene, and thus considerable attention has been paid to the development of eco-friendly and cost-efficient catalysts for this process. Herein, we discover that the Sn-Beta zeolite with Lewis acid sites can activate the C-H bond, and exhibits high catalytic performance in the PDH. XRD, STEM, and XPS characterizations confirm that Sn species are incorporated into the zeolite framework, and H2-TPR suggests that there is a strong interaction between Sn species and zeolite framework. It is found that the Lewis acid is the active site for dehydrogenation reaction, and the Brønsted acid is responsible for cracking reaction. The dehydrogenation rate/cracking rate is positively proportional to the L/B ratio, and a high L/B ratio is beneficial for the propane dehydrogenation reaction. The Na-Sn-Beta-30 catalyst possessing the highest amount of Lewis acid but the lowest Brønsted/Lewis ratio, exhibits the best performance in the PDH, which delivers propane conversion of 40% and propylene selectivity of 92%. Most importantly, these Sn-Beta zeolites are extremely stable without any detectable deactivation under the harsh reaction condition for 72 h. Density functional theory calculations reveal that both Sn and adjacent O atom or OH group cooperatively act as the active sites. The PDH occurs through the direct reaction mechanism in which hydrogen molecule is produced by the direct coupling of H atom of primary C3H7motif with the Brønsted proton in closed sites or the proton of water in open sites. It seems that open sites are more reactive than the closed ones, and the intrinsic enthalpy barriers are calculated to be 242 ~ 301 kJ/mol depending on the hydroxylation extents. These efficient Sn-Beta zeolites could provide a new possibility for the development of a new generation of PDH catalysts with a high stability for the production of propylene.
登录
查看更多内容
影响因子：
7.3
作者：
J. Yun;R. Lobo
通讯作者：
J. Yun;R. Lobo
影响因子：
7.3
作者：
Geomar J. Arteaga;J. Anderson;C. H. Rochester
通讯作者：
Geomar J. Arteaga;J. Anderson;C. H. Rochester
控制 ZrO2 中的配位不饱和 Zr 位点以实现有效的 C-H 键激活
影响因子：
16.6
作者：
Zhang Y;Zhao Y;Otroshchenko T;Lund H;Pohl MM;Rodemerck U;Linke D;Jiao H;Jiang G;Kondratenko EV
通讯作者：
Kondratenko EV
影响因子：
5.2
作者：
Landong Li;N. Guan
通讯作者：
Landong Li;N. Guan
影响因子：
5.5
作者：
G. Aguilar‐Ríos;M. Valenzuela;P. Salas;H. Armendáriz;P. Bosch;G. Toro;R. Silva;V. Bertin;S. Castillo;A. Ramírez‐Solís;I. Schifter
通讯作者：
G. Aguilar‐Ríos;M. Valenzuela;P. Salas;H. Armendáriz;P. Bosch;G. Toro;R. Silva;V. Bertin;S. Castillo;A. Ramírez‐Solís;I. Schifter