Dissociative Carbon Dioxide Adsorption and Morphological Changes on Cu(100) and Cu(111) at Ambient Pressures

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• 作者：Baran Eren ; Robert S. Weatherup ; Nikos Liakakos ; Gabor A. Somorjai ; Miquel Salmeron
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：July 6, 2016
• 年：2016
• 卷：138
• 期：26
• 页码：8207-8211
• 全文大小：392K
• 年卷期：0
• ISSN：1520-5126

文摘

Ambient-pressure X-ray photoelectron spectroscopy (APXPS) and high-pressure scanning tunneling microscopy (HPSTM) were used to study the structure and chemistry of model Cu(100) and Cu(111) catalyst surfaces in the adsorption and dissociation of CO₂. It was found that the (100) face is more active in dissociating CO₂ than the (111) face. Atomic oxygen formed after the dissociation of CO₂ poisons the surface by blocking further adsorption of CO₂. This “self-poisoning” mechanism explains the need to mix CO into the industrial feed for methanol production from CO₂, as it scavenges the chemisorbed O. The HPSTM images show that the (100) surface breaks up into nanoclusters in the presence of CO₂ at 20 Torr and above, producing active kink and step sites. If the surface is precovered with atomic oxygen, no such nanoclustering occurs.