Microwaves effectively examine the extent and type of coking over acid zeolite catalysts.
Microwaves effectively examine the extent and type of coking over acid zeolite catalysts.
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DOI：
10.1038/s41467-017-00602-8
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发表时间：
2017-09-11
影响因子：
16.6
通讯作者：
Edwards PP
中科院分区：
文献类型：
--
作者：
Liu B;Slocombe DR;Wang J;Aldawsari A;Gonzalez-Cortes S;Arden J;Kuznetsov VL;AlMegren H;AlKinany M;Xiao T;Edwards PP
结焦导致固体酸催化剂失活。这一现象是现代石化和能源转化行业中普遍存在的问题。在这里，我们展示了一种基于微波腔微扰分析的方法，用于有效地检查在酸性沸石催化剂上形成的焦炭的数量和化学组成。所采用的微波腔可以快速、非侵入性地测量催化焦化沸石样品的全身渗透性。焦炭总量由获得的介电损耗(ε“)值来反映，其中不同的焦炭成分会导致显著不同的吸收效率(ε”/焦炭重量百分比)。深度脱氢焦炭化合物(如多环芳烃)的ε“/wt%值明显较高，因此可以有效地从轻焦化化合物中分离出来。该测量基于催化反应期间焦炭形成的性质，从饱和状态(例如，脂肪族)到石墨化状态(例如，多芳烃)，由于增强了Maxwell-Wagner极化，获得了更多的离域电子。结焦使催化剂失活是工业过程中的一个主要缺陷。在这里，作者展示了一种非侵入性的微波腔微扰技术，作为一种强有力的工具来确定工业相关沸石催化剂中积炭的性质和程度。
Coking leads to the deactivation of solid acid catalyst. This phenomenon is a ubiquitous problem in the modern petrochemical and energy transformation industries. Here, we show a method based on microwave cavity perturbation analysis for an effective examination of both the amount and the chemical composition of cokes formed over acid zeolite catalysts. The employed microwave cavity can rapidly and non-intrusively measure the catalytically coked zeolites with sample full body penetration. The overall coke amount is reflected by the obtained dielectric loss (ε″) value, where different coke compositions lead to dramatically different absorption efficiencies (ε″/cokes’ wt%). The deeper-dehydrogenated coke compounds (e.g., polyaromatics) lead to an apparently higher ε″/wt% value thus can be effectively separated from lightly coked compounds. The measurement is based on the nature of coke formation during catalytic reactions, from saturated status (e.g., aliphatic) to graphitized status (e.g., polyaromatics), with more delocalized electrons obtained for enhanced Maxwell–Wagner polarization. Catalyst deactivation by coke deposition is a major drawback in industrial processes. Here, the authors show a non-intrusive microwave cavity perturbation technique as a powerful tool to determine the nature and extent of coke accumulation in industrially-relevant zeolite catalysts.
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影响因子：
5.3
作者：
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