Insight into structural distribution of heterogeneous Ziegler-Natta catalyst from non-empirical structure determination
Insight into structural distribution of heterogeneous Ziegler-Natta catalyst from non-empirical structure determination
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DOI：
10.1016/j.jcat.2020.11.005
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发表时间：
2021-02-27
影响因子：
7.3
通讯作者：
Taniike, Toshiaki
中科院分区：
文献类型：
--
作者：
Takasao, Gentoku;Wada, Toru;Taniike, Toshiaki
结构分布是TiCl4-MgCl2纳米板的固有性质，理解它将揭示Ziegler-Natta催化剂产生的聚烯烃一级结构中分布的起源。这样的基本认识是催化剂系统设计的前提之一。在这里，我们对不同尺寸和化学成分的TiCl4-MgCl2纳米板进行了一系列机器学习辅助结构测定。根据在结构测定过程中获得的10(6)个结构，分析了TiCl4的结构和电子分布。这种系统的研究表明：1)TiCl4倾向于以单核物种的形式吸附在{110}表面，而在{100}表面上的吸附是不可忽视的；ii)即使在相同的单核物种的{110}表面，TiCl4的空间环境和荷电状态也是分布的。对乙烯插入的初步考察表明，TiCl4的分布将产生Ziegler-Natta催化剂所获得的聚合物一级结构分布。(C)2020 Elsevier Inc.保留所有权利。
A structural distribution is an intrinsic nature of TiCl4-capped MgCl2 nanoplates, and its comprehension would uncover the origin of distributions in the primary structure of polyolefins produced by Ziegler- Natta catalysts. Such fundamental understanding is one of the prerequisites of the systematic design of catalysts. Here, we performed a series of machine learning-aided structure determination for TiCl4-capped MgCl2 nanoplates of different sizes and chemical compositions. Structural and electronic distributions of TiCl4 were analyzed on the basis of 10(6) structures, which were obtained in the course of the structure determination. Such a systematic investigation revealed that i) TiCl4 tends to adsorb on {110} surfaces as mononuclear species, while adsorption on {100} is not negligible, and that ii) even within the same mononuclear species on {110} surfaces, the steric environment and charge state of TiCl4 are distributed. A preliminary examination on ethylene insertion suggested that the TiCl4 distribution would generate the polymer primary structure distribution obtained by Ziegler-Natta catalysts. (c) 2020 Elsevier Inc. All rights reserved.