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 约翰·M. Vohs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。 该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，以及杂芳族化合物的加氢处理。 HREELS、Auger、RBS、XPS、利兹、STM/AFM;甲醇、甲酸、水、氨和乙胺的TPD;甲醇常压氧化的反应动力学;以及用NH3还原NOx将是表征结构和反应性的主要技术。 这项调查的显着特点是均匀的（可能外延）氧化钒overlayers和支持的O-V键的强度的测定-支持的氧化钒的选择性通常归因于气相沉积。 这种强度将与局部结构和探针分子反应性相关，并且将通过载体的组成和结构而变化。 支持的氧化钒和化学吸附的探针分子的振动特性将确定与HREELS技术具有低至8 cm-1的光谱分辨率。 此外，作者将研究表面-O伸缩模和O-V-O弯曲模，它们比V=O模更能指示支撑相互作用。 表面物种（羟基，氨基，亚硝酰基，甲氧基）将产生的化学吸附和脱附的TPD。 稳态反应（甲醇氧化或NH3的NOx SCR）将在侧面微反应器室中进行，样品可以转移到该室中而不暴露于空气。