Isolating a Reaction Intermediate in the Hydrogenation of 2,2,2-Trifluoroacetophenone on Pt(111)
Isolating a Reaction Intermediate in the Hydrogenation of 2,2,2-Trifluoroacetophenone on Pt(111)
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DOI：
10.1021/acs.jpcc.5b00734
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发表时间：
2015-04-02
影响因子：
3.7
通讯作者：
Hammer, Bjork
中科院分区：
文献类型：
--
作者：
Goubert, Guillaume;Groves, Michael N.;Hammer, Bjork
表面中间体的分离和鉴定对于阐明多相催化的机理和选择性模式是至关重要的。然而，反应中间体的亚稳性质使得它们的检测和与其他物种的区分具有挑战性。本文用变温扫描隧道显微镜(VT-STM)和范德华修正密度泛函理论(OPT88-VDW DFT)相结合的方法研究了2，2，2-三氟苯乙酮(TFAP)氢化生成的羟基中间体(hy-TFAP)被母体TFAP捕获形成氢键的双分子TFAP/hy-TFAP结构。基于先前对TFAP在铂(111)上加氢途径的密度泛函研究，预测了超高真空室中存在的残氢容易形成羟基中间体。通过计算的TFAP/TFAP和TFAP/hy-TFAP结构与不同温度下TFAP吸附和处理形成的双分子结构的STM图像的比较，证实了这一预测。
The isolation and identification of surface intermediates is of the utmost importance for the elucidation of mechanisms and selectivity patterns in heterogeneous catalysis. However, the metastable nature of reaction intermediates makes their detection and differentiation from other species challenging. This work reports a combined variable temperature scanning tunneling microscopy (VT-STM) and van der Waals-corrected density functional theory (opt88-vdW DFT) study showing that a hydroxy intermediate (hy-TFAP) formed in the hydrogenation of 2,2,2-trifluoroacetophenone (TFAP) is trapped by parent TFAP to form a H-bonded bimolecular TFAP/hy-TFAP structure. The facile formation of the hydroxy intermediate, by residual hydrogen present in the ultrahigh vacuum chamber, was predicted based on a previous DFT study of the hydrogenation pathway for TFAP on Pt(111). The prediction is confirmed by comparison of calculated TFAP/TFAP and TFAP/hy-TFAP structures with STM images of bimolecular structures formed through TFAP adsorption and treatment at different temperatures.