Kumar Manish, Dar Manzoor Ahmad, Katiyar Ankita, Agrawal Ravi, Shenai Prathamesh M, Srinivasan Varadharajan
Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal 462 066, India.
Department of Chemistry, Islamic University of Science and Technology, Awantipora, Jammu and Kashmir 192122, India.
Phys Chem Chem Phys. 2022 May 18;24(19):11668-11679. doi: 10.1039/d1cp05769c.
Methane has emerged as a promising fuel due to its abundance and clean combustion properties. It is also a raw material for various value-added chemicals. However, the conversion of methane to other chemicals such as olefins, aromatics, and hydrocarbons is a difficult task. In recent years, ionic iron carbide clusters have been explored as potential catalysts for efficient direct methane conversion. Herein, we have investigated the gas-phase methane conversion process on various neutral iron carbide clusters with different Fe:C ratios using density functional theory. Reaction pathways were studied on mononuclear and trinuclear iron carbide clusters in the three lowest energy spin multiplicity channels. Three descriptors - methane binding energy, the effective energy barrier for C-H bond activation, and the effective energy required for methyl radical evolution - were chosen to identify the best catalyst among the clusters considered. Isomers of FeC (FeC-iso) and FeC (FeC-iso) are recognized as being the most promising catalysts among all the clusters considered here because they require the least methyl radical evolution energy, a step that is crucial in methane conversion to higher hydrocarbon but also requires the most energy.
由于甲烷储量丰富且具有清洁燃烧特性，它已成为一种很有前景的燃料。它也是各种高附加值化学品的原料。然而，将甲烷转化为其他化学品，如烯烃、芳烃和碳氢化合物，是一项艰巨的任务。近年来，离子型碳化铁簇已被探索作为高效直接甲烷转化的潜在催化剂。在此，我们使用密度泛函理论研究了不同Fe:C比的各种中性碳化铁簇上的气相甲烷转化过程。在三个最低能量自旋多重度通道中，对单核和三核碳化铁簇的反应路径进行了研究。选择了三个描述符——甲烷结合能、C-H键活化的有效能垒以及甲基自由基生成所需的有效能量——来确定所考虑的簇中最佳的催化剂。在本文所考虑的所有簇中，FeC（FeC-iso）和FeC（FeC-iso）的异构体被认为是最有前景的催化剂，因为它们所需的甲基自由基生成能量最少，这一步骤在甲烷转化为高级烃的过程中至关重要，但同时也是能量需求最高的一步。
