Alkane Oxidation on Rh(111) Single-Crystal Surfaces under High-Temperature, Short-Contact-Time Conditions: A Molecular Beam Kinetic Study†
Alkane Oxidation on Rh(111) Single-Crystal Surfaces under High-Temperature, Short-Contact-Time Conditions: A Molecular Beam Kinetic Study†
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高温、短接触时间条件下 Rh(111) 单晶表面上的烷烃氧化：分子束动力学研究†
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发表时间：
2010
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通讯作者：
F. Zaera
中科院分区：
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作者：
Jarod N Wilson;F. Zaera
本文用平行发散分子束研究了Rh（111）单晶表面上分子氧部分氧化烷烃的动力学。这些实验被认为是在高温、短接触时间条件下探索这些过程的机制的细节。据确定，在这些反应中的主要产品是H2和CO，合成气的组分，因为它已经提出了所谓的直接机制。水的产生也被检测到，但由于所涉及的表面羟基中间体的缓慢形成，所以以较慢的速率。另一方面，二氧化碳永远不会产生，因为一氧化碳在有机会与吸附的氧原子进一步反应之前解吸。表面和表面下的原子氧物种的形式在反应过程中，但只有更不稳定的表面中间体是相关的，阻塞Rh网站烷烃活化和反应，形成CO和H2O。
The kinetics of the partial oxidation of alkanes with molecular oxygen on Rh(111) single-crystal surfaces were studied by using a collimated effusive molecular beam under ultrahigh vacuum conditions. These experiments were conceived to probe the details of the mechanism of these processes under high-temperature, short-contact-time conditions. It was determined that the primary products in these reactions are H2 and CO, the components of syngas, as it has been suggested by the so-called direct mechanism. The production of water is also detected, but at a slower rate because of the slow formation of the surface hydroxo intermediate involved. Carbon dioxide, on the other hand, is never produced, because carbon monoxide desorbs before having the opportunity to react further with adsorbed oxygen atoms. Both surface and subsurface atomic oxygen species form during the reaction, but only the more labile surface intermediate is relevant, blocking Rh sites for alkane activation and reacting to form CO and H2O.