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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Substrate Vibrations as Promoters of Chemical Reactivity on Metal Surfaces
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Substrate Vibrations as Promoters of Chemical Reactivity on Metal Surfaces

机译：基底振动是金属表面化学反应的促进剂

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摘要

Studies exploring how vibrational energy (E-vib) promotes chemical reactivity most often focus on molecular reagents, leaving the role of substrate atom motion in heterogeneous interfacial chemistry underexplored. This combined theoretical and experimental study of methane dissociation on Ni(111) shows that lattice atom motion modulates the reaction barrier height during each surface atoms vibrational period, which leads to a strong variation in the reaction probability (S-0) with surface temperature (T-surf). State-resolved beam-surface scattering studies at T-surf = 90 K show a sharp threshold in S-0 at translational energy (E-trans) = 42 kJ/mol. When Etrans decreases from 42 kJ/mol to 34 kJ/mol, S-0 decreases 1000-fold at T-surf = 90 K, but only 2-fold at T-surf = 475 K. Results highlight the mechanism for this effect, provide benchmarks for DFT calculations, and suggest the potential importance of surface atom induced barrier height modulation in heterogeneously catalyzed reactions, particularly on structurally labile nanoscale particles and defect sites.
机译：研究振动能（E-vib）如何促进化学反应的研究最常集中在分子试剂上，而底物原子运动在异质界面化学中的作用尚待研究。甲烷与Ni（111）上的甲烷解离的理论和实验相结合的研究表明，晶格原子运动会在每个表面原子振动周期内调节反应势垒高度，从而导致反应概率（S-0）随表面温度的变化很大（ T-surf）。 T-surf = 90 K时的状态分辨束面散射研究表明，在平移能量（E-trans）= 42 kJ / mol时，S-0的阈值很高。当Etrans从42 kJ / mol降至34 kJ / mol时，S-0在T-surf = 90 K时降低1000倍，而在T-surf = 475 K时仅降低2倍。结果突出了这种效应的机理，提供了DFT计算的基准，并提出了表面原子诱导的势垒高度调节在非均相催化反应中的潜在重要性，特别是在结构上不稳定的纳米级颗粒和缺陷位点上。

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