Oxide supported metal catalysis, structure reactivity studies

氧化物负载的金属催化剂是从排放物修复到烃氧化到燃料电池技术的多相过程中的关键材料。这些催化剂通常涉及分散在氧化物如二氧化硅、氧化铝或氧化锆基质中的纳米至微米尺寸的分散金属颗粒。尽管它们被广泛使用，但对于氧化物负载的金属催化剂，许多问题仍然没有答案：载体的作用是什么？活跃的网站有哪些？反应机理是什么？中间体是什么，它们是如何干扰反应的？即使在极高的负载量的情况下，用于燃料电池的电催化剂，活性位点，机制和中间体的问题仍然不清楚，拟议的研究计划的目标是解决这些问题，通过建立结构反应性关系和研究中间体在原位。由于载体材料的差异以及催化剂负载的巨大差异，低负载和高负载材料之间相互作用的潜力尚未被认识到。我们打算在分子水平上研究氧化钇稳定的氧化锆上的金属纳米颗粒上发生的过程，因为它们在多相催化以及固体氧化物燃料电池工业中的潜力。实验方法涉及多孔“真实的”催化剂的制备和测试。使用衍射和显微镜技术对这些材料的电子和形态结构进行了充分表征，并对反应堆或燃料电池装置中的活性进行了测试。同时，在超高真空条件下使用光谱学和显微镜研究了“模型”催化剂。模型催化剂和真实的催化剂的结构-反应性关系的比较对于理解和改进催化过程具有很好的潜力。该方法旨在为制备具有所需性能的催化剂提供理论基础。

Oxide supported metal catalysts are key materials in heterogeneous processes ranging from emissions remediation to hydrocarbon oxidation to fuel cell technology. These catalysts generally involve disperse metal particles of nano to micrometer size dispersed in the matrix of an oxide such as silica, alumina or zirconia. Despite their widespread use, many questions remain unanswered for oxide supported metal catalysts: what is the role of the support?, what are the active sites?, what are the reaction mechanisms?, what are the intermediates and how do they interfere with the reaction? Even in the extremely high loading cases used in the electro-catalysts of fuel cells, issues regarding active sites, mechanism, and intermediates remain unclear.The objective of the proposed research program is to address some of these questions by establishing structure-reactivity relationships and studying intermediates in situ. The potential for interplay between low and high loading materials has gone unrecognized owing to differences in support material as well as dramatic differences in catalyst loading. We intend to study, at the molecular level, the processes occurring on metal nanoparticles supported on yttria stabilised zirconia due to their potential in heterogeneous catalysis as well as in the solid oxide fuel cell industry.The experimental approach involves the preparation and testing of porous "real" catalysts. These materials are fully characterised for electronic and morphological structure using diffraction and microscopy techniques and tested for activity in reactor or fuel cell setups. At the same time, "model" catalysts are studied under ultra high vacuum conditions using spectroscopy and microscopy. The comparison of structure-reactivity relationships obtained for model catalysts and for real catalyst has a good potential for the understanding and improvement of catalytic processes. The approach is meant to provide a rationale for targeting the preparation of catalysts with the desired properties.