Competitive paths for methanol decomposition on Pt(111)
Competitive paths for methanol decomposition on Pt(111)
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DOI：
10.1021/ja037700z
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发表时间：
2004-03-31
影响因子：
15
通讯作者：
Mavrikakis, M
中科院分区：
文献类型：
--
作者：
Greeley, J;Mavrikakis, M
采用周期性、自洽的密度泛函理论（PW 91-GGA）方法研究了甲醇在Pt（111）上分解的竞争路径。考虑通过甲醇中的初始C-H和C-O键断裂事件进行的途径，并将结果与通过初始O-H断裂事件进行的途径的数据进行比较[格里利等人，J. Am. 2002，124，7193]。DIFT的结果表明，甲醇分解通过CH 2 OH和甲醛或HCOH中间体是一个积极可行的途径; O-H断裂到CH 3 O，然后依次脱氢，可能是另一个现实的路线。基于第一性原理的微观动力学模拟结果表明，在实际反应条件下，甲醇中的C-H断裂是净速率最高的初始分解步骤。所有反应途径的基本步骤（除了C-O断裂）遵循过渡态和终态能量之间的线性相关性。模拟的HREELS光谱的中间体显示出良好的协议与现有的实验数据，HREELS光谱实验难以捉摸的反应中间体的预测。
Periodic, self-consistent, Density Functional Theory (PW91-GGA) calculations are used to study competitive paths for the decomposition of methanol on Pt(111). Pathways proceeding through initial C-H and C-O bond scission events in methanol are considered, and the results are compared to data for a pathway proceeding through an initial O-H scission event [Greeley et al. J. Am. Chem. Soc. 2002, 124, 7193]. The DIFT results suggest that methanol decomposition via CH2OH and either formaldehyde or HCOH intermediates is an energetically feasible pathway; O-H scission to CH3O, followed by sequential dehydrogenation, may be another realistic route. Microkinetic modeling based on the first-principles results shows that, under realistic reaction conditions, C-H scission in methanol is the initial decomposition step with the highest net rate. The elementary steps of all reaction pathways (with the exception of C-O scission) follow a linear correlation between the transition state and final state energies. Simulated HREELS spectra of the intermediates show good agreement with available experimental data, and HREELS spectra of experimentally elusive reaction intermediates are predicted.