Theoretical study on the gas‐phase reaction mechanism between nickel monoxide and methane for syngas production
Theoretical study on the gas‐phase reaction mechanism between nickel monoxide and methane for syngas production
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DOI：
10.1002/jcc.21205
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发表时间：
2009-04
影响因子：
3
通讯作者：
Huaqing Yang;Song Qin;Changwei Hu
中科院分区：
文献类型：
--
作者：
Huaqing Yang;Song Qin;Changwei Hu
在B3 LYP/6 - 311++G（3df，3 pd）//B3 LYP/6 - 311+G（2d，2 p）水平上，在三重态和单重态势能面上对一氧化镍与甲烷气相反应生成合成气、甲醛、甲醇、水和甲基自由基的反应机理进行了全面的研究.计算结果表明，单重态中间体HNiOCH 3是合成气形成的关键，而两种重要的反应中间体CH 3 NiOH和HNiOCH 3位于深阱中，而CH 3 NiOH在三重态和单重态上都比HNiOCH 3更有利于能量的产生.一旦在单重态上产生HNiOCH 3，则主要产物应为合成气，而如果在单重态和三重态上均形成CH 3 NiOH，则主要产物应为甲基自由基。对于合成气的形成，最小能量反应途径（MERP）在能量上更优选从最低激发单重态而不是从基态三重态开始。在合成气形成的MERP中，速率决定步骤（RDS）是单重态中间体HNiOCH 3形成的反应步骤，涉及NiO分子氧化加成到甲烷的C-OH键中，能量势垒为120.3 kJ mol−1。在较高的温度和较高的光解反应条件下，合成气的形成将更有效。© 2009 Wiley Periodicals，Inc.《计算化学杂志》，2009年
The comprehensive mechanism survey on the gas‐phase reaction between nickel monoxide and methane for the formation of syngas, formaldehyde, methanol, water, and methyl radical has been investigated on the triplet and singlet state potential energy surfaces at the B3LYP/6‐311++G(3df, 3pd)//B3LYP/6‐311+G(2d, 2p) levels. The computation reveals that the singlet intermediate HNiOCH3 is crucial for the syngas formation, whereas two kinds of important reaction intermediates, CH3NiOH and HNiOCH3, locate on the deep well, while CH3NiOH is more energetically favorable than HNiOCH3 on both the triplet and singlet states. The main products shall be syngas once HNiOCH3 is created on the singlet state, whereas the main products shall be methyl radical if CH3NiOH is formed on both singlet and triplet states. For the formation of syngas, the minimal energy reaction pathway (MERP) is more energetically preferable to start on the lowest excited singlet state other than on the ground triplet state. Among the MERP for the formation of syngas, the rate‐determining step (RDS) is the reaction step for the singlet intermediate HNiOCH3 formation involving an oxidative addition of NiO molecule into the CH bond of methane, with an energy barrier of 120.3 kJ mol−1. The syngas formation would be more effective under higher temperature and photolysis reaction condition. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009