Surface Science Studies of Model Supported Vanadia Catalysts

模型支持的氧化钒催化剂的表面科学研究

• 批准号: 9712774
• 负责人: John Vohs
• 金额: $ 30万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-01 至 2002-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9712774&HistoricalAwards=false
• 关键词: Surface; Science; Studies; Model; Supported

Abstract - Vohs 9712774 Professor John M. Vohs, of University of Pennsylvania, will investigate the structure and reactivity of model vanadia catalysts supported on single crystal titania, ceria, zirconia, and magnesia. This fundamental research is of relevance to various industrial processes, such as selective oxidation and ammoxidation of hydrocarbons and alcohols, reduction of nitrogen oxides by ammonia and hydrocarbons, and hydrotreatment of heteroaromatics. HREELS, Auger, RBS, XPS, LEEDS, STM/AFM; TPD of methanol, formic acid, water, ammonia and ethylamine; reaction kinetics of the atmospheric pressure oxidation of methanol; and reduction of NOx with NH3 will be the primary techniques to characterize structure and reactivity. The distinctive feature of this investigation is the vapor deposition of uniform (possibly epitaxial) vanadia overlayers and the determination of the strength of the support-O-V bonds -- to which the selectivity of supported vanadia is usually attributed. Such strength will be correlated with local structure and probe molecule reactivity, and will be varied by the composition and structure of the support. The vibrational characteristics of both supported vanadia and chemisorbed probe molecules will be determined with an HREELS technique having spectral resolution as low as 8 cm-1. In addition, the author will study the surface-O stretching modes, and the O-V-O bending modes, which are more indicative of support interaction than the V=O mode. Surface species (hydroxyl, amino, nitrosyl, methoxy) will be produced by chemisorption and desorbed by TPD. The steady state reactions (methanol oxidation or NOx SCR with NH3) will be carried out on a side microreactor chamber to which samples can be transferred without air exposure.

摘要 - Vohs 9712774 宾夕法尼亚大学的 John M. Vohs 教授将研究负载在单晶二氧化钛、二氧化铈、氧化锆和氧化镁上的模型氧化钒催化剂的结构和反应性。 这项基础研究与各种工业过程相关，例如烃和醇的选择性氧化和氨氧化、氨和烃还原氮氧化物以及杂芳烃的加氢处理。 HREELS、俄歇、RBS、XPS、LEEDS、STM/AFM；甲醇、甲酸、水、氨、乙胺的TPD；甲醇常压氧化反应动力学；用NH3还原NOx将是表征结构和反应性的主要技术。 这项研究的显着特点是均匀（可能是外延）氧化钒覆盖层的气相沉积以及载体-O-V键强度的测定——负载型氧化钒的选择性通常归因于此。 这种强度将与局部结构和探针分子反应性相关，并且将根据支持物的组成和结构而变化。 负载的氧化钒和化学吸附的探针分子的振动特性将通过光谱分辨率低至 8 cm-1 的 HREELS 技术来确定。 此外，作者还将研究表面-O拉伸模式和O-V-O弯曲模式，它们比V=O模式更能说明支撑相互作用。 表面物质（羟基、氨基、亚硝基、甲氧基）将通过化学吸附产生并通过 TPD 解吸。 稳态反应（甲醇氧化或使用 NH3 的 NOx SCR）将在侧面微反应器室中进行，样品可以在不暴露于空气的情况下转移到该室中。