CO2 desorption dynamics on specified sites and surface phase transitions of Pt(110) in steady-state CO oxidation
CO2 desorption dynamics on specified sites and surface phase transitions of Pt(110) in steady-state CO oxidation
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DOI：
10.1063/1.1615473
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发表时间：
2003-11
影响因子：
4.4
通讯作者：
I. Rzeznicka;Md. Goula Moula;L. M. Garza;Y. Ohno;T. Matsushima
中科院分区：
文献类型：
--
作者：
I. Rzeznicka;Md. Goula Moula;L. M. Garza;Y. Ohno;T. Matsushima
研究了CO在Pt~110！通过互相关飞行时间技术。利用LEED技术对催化反应过程中的表面结构变化进行了监测。在表面高度重构为缺失行形式的活动区，CO2解吸分裂成两个方向性的波瓣，在包括@001 #方向的平面内与表面法线成沿着25°，表明CO2形成于倾斜的~111！露台。平移温度在准直角处达到最大值，达到约1900 K。另一方面，CO2解吸急剧准直沿着表面正常的CO压力，其中~132！域消失了。在CO压力下，半级LEED斑点已经消失，从倾斜脱附到正向脱附的分布变化是突然的。这个转换点比LEED对~132！131！然后用于构建在从1310 27托到1310 24托的氧气压力范围内的工作反应位点的表面相图。在~132！随着CO压力的增加。© 2003年美国物理研究所。@DOI：10.1063/1.1615473#
The spatial and velocity distributions of desorbing product CO2 were studied in the steady-state CO oxidation on Pt~110! by cross-correlation time-of-flight techniques. The surface structure transformation was monitored by LEED in the course of the catalyzed reaction. In the active region, where the surface was highly reconstructed into the missing-row form, CO 2 desorption split into two directional lobes collimated along 25° from the surface normal in the plane including the @001# direction, indicating the CO2 formation on inclined ~111! terraces. The translational temperature was maximized at the collimation angle, reaching about 1900 K. On the other hand, CO2 desorption sharply collimated along the surface normal at CO pressures where ~132! domains disappeared. The distribution change from an inclined desorption to a normally directed one was abrupt at the CO pressure where the half-order LEED spot already disappeared. This switching point was more sensitive than LEED towards the complete transformation from ~132! to ~131! and was then used to construct a surface phase diagram for working reaction sites in the pressure range from 1310 27 Torr to 1310 24 Torr of oxygen. The turnover frequency of CO2 formation was enhanced on ~132! domains with increasing CO pressure. © 2003 American Institute of Physics. @DOI: 10.1063/1.1615473#