Insights into Coke Formation and Removal under Operating Conditions with a Quantum Nanoreactor Approach,The Journal of Physical Chemistry Letters

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Insights into Coke Formation and Removal under Operating Conditions with a Quantum Nanoreactor Approach
The Journal of Physical Chemistry Letters ( IF 4.8 ) Pub Date : 2021-09-23 , DOI: 10.1021/acs.jpclett.1c02892
Tingyu Lei _{1,

2} , Xingchen Liu ₁ , Amar Deep Pathak ₃ , Sharan Shetty ₃ , Qingya Liu ₂ , Xiaodong Wen _{1,

4}

Affiliation

The in situ formation and removal of coke is a critical problem in heterogeneous catalysis, but its mechanism is not well understood. This work investigates the mechanism of carbon deposition and hydrogenation on an Fe cluster under high-temperature conditions with the density functional tight-binding (DFTB) based nanoreactor molecular dynamics (NMD) method. Our study shows that successive formation of carbon chains, rings, and fused rings occurred during the carbon deposition on Fe clusters. Hydrogenation of activated carbon happens through direct C–H coupling, while the hydrogenation of graphitic carbon involves hydrogenation of the edge carbon, ring-opening reaction, and dealkylation reaction. The main function of the Fe catalyst is to provide the active sites for H₂ dissociation and dissociated H spillover, while its activity toward C–C bond breaking is limited. These results highlight the role of the DFTB-NMD method as an effective tool to investigate reaction mechanisms under operating conditions in heterogeneous catalysis.

中文翻译：

使用量子纳米反应器方法深入了解操作条件下焦炭的形成和去除

该原位焦炭的形成和去除是在多相催化的一个关键问题，但其作用机制还不是很清楚。这项工作使用基于密度泛函紧束缚 (DFTB) 的纳米反应器分子动力学 (NMD) 方法研究了高温条件下 Fe 簇上碳沉积和氢化的机制。我们的研究表明，碳链、环和稠环的连续形成发生在 Fe 簇上的碳沉积过程中。活性炭的加氢通过直接的 C-H 偶联发生，而石墨碳的加氢涉及边缘碳的加氢、开环反应和脱烷基化反应。Fe催化剂的主要功能是为H ₂提供活性位点解离和解离的 H 溢出，而其对 C-C 键断裂的活性是有限的。这些结果突出了 DFTB-NMD 方法作为研究多相催化操作条件下反应机理的有效工具的作用。

更新日期：2021-10-07

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