DNP NMR reveals the hidden surface C–C bond growth mechanism over ZnAlOx during syngas conversion
DNP NMR reveals the hidden surface C–C bond growth mechanism over ZnAlOx during syngas conversion
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DNP NMR 揭示了合成气转化过程中 ZnAlOx 上隐藏的表面 C–C 键生长机制
DOI：
10.1016/j.jechem.2021.10.033
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发表时间：
2022
影响因子：
13.1
通讯作者：
Bao Xinhe
中科院分区：
文献类型：
--
作者：
Gao Pan;Xiao Dong;Zhao Zhenchao;Paul Subhradip;Blanc Frédéric;Han Xiuwen;Hou Guangjin;Bao Xinhe
© 2021科学出版社和中国科学院大连化学物理研究所。出版社：ELSEVIER BV and Science Press合成气（CO/H2）直接催化转化为高附加值的碳氢化合物一直是C1化学中最具吸引力但又最具挑战性的问题之一。近年来，氧化物-沸石（OXZEO）双功能催化的概念出现，并激发了该领域的新热情[1，2]。该方法描述了使用选择的氧化物-沸石基复合催化剂用于合成气直接转化为烃，其中氧化物和沸石组分以串联方式配合用于初始合成气活化和进一步的形状选择性转化，从而获得超过传统方法的高目标产物选择性[3，4]。迄今为止，多篇报道已经提出了通过这种方法从合成气选择性合成乙烯[5，6]、低级烯烃[7-9]、芳族化合物[10-14]和汽油范围产物[15]。然而，对该反应的机理理解仍然有限，特别是当涉及氧化物催化剂上的初始反应时。氧化物表面上初始C-C键的形成和生长一直是主要关注的问题。研究人员分别检测到甲醇/二甲醚（DME）（C1物质）[4]和乙烯酮（C2物质）[3]作为从氧化物表面分离的初始中间体。此外，据报道，在氧化物表面上的合成气转化过程中产生了明显量的C2+烷烃/烯烃[5，9]，这是氧化物表面上C-C键生长的更具体证据。然而，尽管研究人员采用原位光谱来探索氧化物部分的反应，但观察到的表面物质/中间体仅限于C1物质[7，9]，没有提供表面C-C键形成的线索。弄清楚
© 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER BV and Science Press. All rights reserved.Direct catalytic transformation of syngas (CO/H2) into high value-added hydrocarbons has been one of the most attractive, yet challenging issues in C1 chemistry. In recent years, the concept of oxide-zeolite (OXZEO) bifunctional catalysis has emerged and spurred renewed enthusiasm in this field [1, 2]. This method describes the use of selected oxide-zeolite-based composite catalysts for the direct syngas-to-hydrocarbons conversion, where the oxide and zeolite components cooperate in a tandem manner for initial syngas activation and further shape-selective transformation, thus attaining a high target product selectivity which surpassed traditional methods [3, 4]. To date, multiple reports have presented the selective synthesis of ethylene [5, 6], lower olefins [7–9], aromatics [10–14] and gasoline range products [15] from syngas via this very method. Yet, mechanistic understanding on this reaction remains limited, especially when concerned with the initial reactions over the oxide catalysts. The initial C–C bond formation and growth on the oxide surface has been a major concern. As researchers have separately detected methanol/dimethyl ether (DME)(C1 species)[4] and ketene (C2 species)[3] as initial intermediates that detached from the oxide surface. Besides, C2+ alkanes/alkenes were reported to produce in evident amounts during syngas conversion on the oxide surface [5, 9], which is a more concrete evidence of C–C bond growth on the oxide surface. However, though researchers have adopted in situ spectroscopy to explore the reaction over the oxide part, the observed surface species/intermediates has been limited to C1 species [7, 9], providing no clue on the surface C–C bond formation. Figuring out how the