THE INTERACTION OF CH4 AT HIGH-TEMPERATURES WITH CLEAN AND OXYGEN PRECOVERED CU(100)
THE INTERACTION OF CH4 AT HIGH-TEMPERATURES WITH CLEAN AND OXYGEN PRECOVERED CU(100)
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DOI：
10.1016/0039-6028(92)90168-6
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发表时间：
1992-03-01
期刊：
影响因子：
1.9
通讯作者：
ULLMANN, S
中科院分区：
文献类型：
--
作者：
ALSTRUP, I;CHORKENDORFF, I;ULLMANN, S
用XPS研究了800-1000 K温度范围内CH 4在Cu（100）上的分解。 此外，在700-800 K温度范围内，还研究了CH_4与吸附在Cu（100）表面的氧的相互作用。 在两种情况下，CH 4的压力均为10托。 在高于约800 K的温度下观察到清洁表面上的可测量的沉积。 解离化学吸附几率极低，在1000 K时约为8.6 × 10 ~（-9）。 清洁表面上的化学吸附概率的活化能（初始“粘附系数”）约为201 kJ/mol。 饱和层中的碳量和C lsXPS结合能表明在表面上形成石墨层。 碳生长曲线的形状表明，该层是通过石墨岛的生长形成的。 在低于700 K的温度下，CH 4气体分子已经与化学吸附在Cu（100）上的氧原子反应。 在氧覆盖度θ（o）几乎等于0.5ML时，初始反应速率的活化能约为125 kJ/mol。
The decomposition of CH4 on Cu(100) has been studied by XPS in the temperature range 800-1000 K. In addition the interaction of CH4 with oxygen adsorbed on Cu(100) has been studied in the temperature range 700-800 K. In both cases the pressure of CH4 was 10 Torr. Measurable deposition on the clean surface was observed at temperatures above about 800 K. The dissociative chemisorption probability is exceedingly low, about 8.6 x 10(-9) at 1000 K. The activation energy of the chemisorption probability on the clean surface (the initial "sticking coefficient") is about 201 kJ/mol. The amount of carbon in the saturation layer and the C ls XPS binding energy show that a graphite layer is formed on the surface. The shape of the carbon growth curves indicate that the layer is formed through the growth of graphite islands. The CH4 gas molecules react with oxygen atoms chemisorbed on Cu(100) already at temperatures below 700 K. The activation energy of the initial reaction rate at an oxygen coverage theta(o) almost-equal-to 0.5 ML is about 125 kJ/mol.