Elucidating the Role of Basic Promoters in Transition Metal Catalysis

摘要- Davis - 9729812 弗吉尼亚大学的Robert J. Davis教授将研究碱土元素和稀土氧化物对氨合成反应的负载型Ru金属催化剂的促进机理。这一建议与催化科学有关，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有更广泛的关系。在碱促进的Ru催化剂上的氨合成可以导致降低的工艺能量消耗，从而减少对环境的影响。Ru金属的碱性促进剂将包括碱金属和碱土金属以及稀土金属氧化物：例如K、Ba、Ca以及Ce和Pr的氧化物。载体将包括沸石、其它氧化物和碳。建议的目标是确定Ru团簇的原子结构EXAFS和它们的电子结构的XANES和红外光谱的吸附N2。在附近的促进剂分布，并在Ru簇在非沸石支持，将通过分析HRTEM检查，并与乙烷氢解活性。活性位点的密度将用N2和H2化学吸附的TPD测定，并且它们的固有活性通过N2活化和通过NH3合成在大气压和20巴压力下测定。各种活性中间体的表面覆盖率将通过稳态同位素瞬态动力学进行研究。

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.