Elucidating the Role of Basic Promoters in Transition Metal Catalysis

阐明碱性促进剂在过渡金属催化中的作用

• 批准号: 9729812
• 负责人: Robert Davis
• 金额: $ 30.35万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-03-01 至 2003-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9729812&HistoricalAwards=false
• 关键词: Elucidating; Role; Basic; Promoters; Transition

Abstract- Davis - 9729812 Prof. Robert J. Davis of the University of Virginia will investigate the mechanism of promotion of supported Ru metal catalysts for the ammonia synthesis reaction, by alkaline-earth elements and rare-earth oxides. This proposal is of relevance to the science of catalysis and of wider relevance to the chemical industry, in particular that concerned with agrochemical and commodity chemical production. Ammonia synthesis over base-promoted Ru catalysts may lead to reduced consumption of process energy and consequently less environmental impact. Basic promoters for Ru metal will include alkali and alkaline-earth as well as rare-earth oxides: K, Ba, Ca, and oxides of Ce and Pr, for example. Supports will include zeolites, other oxides, and carbon. The proposal objectives are to determine the atomic structure of Ru clusters by EXAFS and their electronic structure by XANES and IR spectroscopy of adsorbed N2. The promoter distribution in the vicinity of, and on Ru clusters over non-zeolitic supports, will be examined by analytical HRTEM, and correlated with ethane hydrogenolysis activity. The density of active sites will be determined with TPD of N2 and H2 chemisorption, and their intrinsic activity by N2 activation and by NH3 synthesis at atmospheric and at 20-bar pressure. The surface coverage by various reactive intermediates will be investigated by means of steady state isotopic transient kinetics.

美国弗吉尼亚大学教授Robert J.Davis-9729812将研究碱土元素和稀土氧化物对负载型Ru金属催化剂在氨合成反应中的促进作用机理。这一建议与催化科学有关，并与化学工业，特别是与农用化学品和商品化学品生产有关的化学工业具有更广泛的相关性。在碱促进的Ru催化剂上合成氨可以降低工艺能耗，从而减少对环境的影响。Ru金属的碱性促进剂将包括碱和碱土，以及稀土氧化物：K，Ba，Ca，以及Ce和Pr的氧化物。载体将包括沸石、其他氧化物和碳。建议的目标是用EXAFS确定Ru团簇的原子结构，用XANES和吸附的N_2的红外光谱确定它们的电子结构。非沸石载体上Ru团簇附近和上的助剂分布将通过分析HRTEM进行检验，并与乙烷氢解活性相关联。活性中心的密度将由N_2和H_2化学吸附的TPD以及它们的本征活性通过N_2活化和常压和20巴压力下的NH_3合成来确定。各种活性中间体的表面覆盖率将通过稳态同位素瞬变动力学进行研究。