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教授将调查支持单晶钛，陶瓷，氧化氧化和镁的模型Vanadia催化剂的结构和反应性。 这项基本研究与各种工业过程有关，例如碳氢化合物和酒精的选择性氧化和氧化剂，氨和碳氢化合物减少氮氧化物，以及杂芳烃的水力处理。 Hreels，Auger，RB，XPS，Leeds，STM/AFM；甲醇，甲酸，水，氨和乙胺的TPD；甲醇大气压氧化的反应动力学； NH3用NOX的减少将是表征结构和反应性的主要技术。 这项研究的独特特征是均匀（可能是外延）Vanadia叠加剂的蒸气沉积以及支持-O-V键的强度 - 通常将支持的Vanadia的选择性归因于此。 这种强度将与局部结构和探针分子反应性相关，并将随支撑的组成和结构而变化。 支持的Vanadia和化学吸附探针分子的振动特性将通过具有低至8 cm-1的光谱分辨率的HREELS技术确定。 此外，作者将研究表面-O伸展模式和O-V-O弯曲模式，而O-V-O弯曲模式比V = O模式更有指示支持相互作用。 表面物种（羟基，氨基，亚硝基，甲氧基）将通过化学吸收产生，并通过TPD解吸。 稳态反应（甲醇氧化或与NH3的NOX SCR）将在侧面微反应室进行，可以将样品转移到而无需空气的情况下。