Synergistic Effects of VOx鈥揚t Probed by the Oxidation of Propane on VOx/Pt(111)

详细信息    查看全文

• 作者：Yanping Zheng ; Lihua Zhang ; Shaolin Wang ; Ding Ding ; Hong Zhang ; Mingshu Chen ; Huilin Wan
• 刊名：Langmuir
• 出版年：2013
• 出版时间：July 23, 2013
• 年：2013
• 卷：29
• 期：29
• 页码：9090-9097
• 全文大小：501K
• 年卷期：v.29,no.29(July 23, 2013)
• ISSN：1520-5827

文摘

VO_x/Pt(111), which was grown layer-by-layer and exhibited a well-defined structure, was used as a model catalytic surface to study the intrinsic catalytic activity of Pt, as well as the effect of VO_x additive, for the oxidation of propane. A special sample system was designed to ensure a reliable analysis of the trace amount of model catalytic reaction products. The results show that the catalytic activities for the oxidation of C₃H₈ on the Pt(111) surface as adding VO_x are suppressed apparently at temperatures below 400 K, but enhanced significantly at temperatures above 400 K. Maximum reaction rates are achieved at a VO_x coverage of about 0.3 ML at the test temperatures of 423 and 473 K. The infrared reflection鈥揳bsorption spectroscopy (IRAS) results show that the redox property of the VO_x鈥揚t is much better than that of the bulklike VO_x. This is confirmed by CO poisoning tests, in that the oxidation of VO_x/Pt(111) is significantly suppressed by the coadsorbed CO. The kinetic data demonstrate that there are at least two catalytically active sites, metallic Pt and VO_x鈥揚t interface, for the activation and oxidation of C₃H₈. The promotion effects of VO_x on Pt for the oxidation of C₃H₈ can be attributed to the synergy between VO_x and Pt.