Eren Baran, Kersell Heath, Weatherup Robert S, Heine Christian, Crumlin Ethan J, Friend Cynthia M, Salmeron Miquel B
Paulson School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States.
Department of Materials Science and Engineering, University of California , Berkeley, California 94720, United States.
J Phys Chem B. 2018 Jan 18;122(2):548-554. doi: 10.1021/acs.jpcb.7b04681. Epub 2017 Aug 14.
Using ambient pressure X-ray photoelectron spectroscopy (APXPS) and high pressure scanning tunneling microscopy (HPSTM), we show that in equilibrium with 0.01-0.2 Torr of methanol vapor, at room temperature, the Cu(100) surface is covered with methoxy species forming a c(2 × 2) overlayer structure. In contrast, no methoxy is formed if the surface is saturated with an ordered oxygen layer, even when the methanol pressure is 0.2 Torr. At oxygen coverages below saturation, methanol dissociates and reacts with the atomic oxygen, producing methoxy and formate on the surface, and formaldehyde that desorbs to the gas phase. Unlike the case of pure carbon monoxide and carbon dioxide, methanol does not induce the restructuring of the Cu(100) surface. These results provide insight into catalytic anhydrous production of aldehydes.
通过使用常压X射线光电子能谱（APXPS）和高压扫描隧道显微镜（HPSTM），我们发现，在室温下与0.01 - 0.2托的甲醇蒸气达到平衡时，Cu(100)表面覆盖有形成c(2×2)重叠层结构的甲氧基物种。相比之下，如果表面被有序的氧层饱和，即使甲醇压力为0.2托，也不会形成甲氧基。在低于饱和的氧覆盖度下，甲醇会解离并与原子氧反应，在表面产生甲氧基和甲酸盐，以及解吸到气相中的甲醛。与纯一氧化碳和二氧化碳的情况不同，甲醇不会诱导Cu(100)表面的重构。这些结果为醛的催化无水生产提供了见解。
