Dynamic Structure of Graphite-Supported Iron-Iridium and Iron-Palladium Catalyst Particles

负载型铁铑催化剂的前期工作 碳被扩展到另外两个系统：铁-铱 和铁钯。 先前的研究表明， 预处理条件产生不同的表面状态 的铁铑合金，范围从孤立的 （分离）金属到紧密合金。 初步研究 对铁铱的影响不仅表明偏析效应 在这个系统中发生，但它可以获得 与铱相关的高活性催化剂， 显示出与许多 活性铁较少。 在这项研究中，铁铱和铁- 使用穆斯堡尔光谱研究钯催化剂， X射线衍射，电子显微镜，量热法，和 反应探针 起始反应探针为1-丁烯 氢化/异构化。 这项工作因其实际意义而令人兴奋。 欧盟采用汽车排放标准 社区对世界供应造成了巨大的压力， 贵金属，许多研究的一个主要目标是 开发不依赖于 这些非常昂贵和稀缺的材料。 这种方法 这并不能消除对贵金属的需求，但它极大地 减少了所需的量，可能高达80%， 用容易获得的铁代替它。工作也 这对于深入了解合金的形成和稳定性具有重要意义。

Earlier work on iron-rhodium bimetallic catalysts supported on carbon is extended to two additional systems: iron-iridium and iron-palladium. The previous study showed that varying the pretreatment conditions produced different surface states of the iron-rhodium bimetallic, ranging from isolated (separate) metals to an intimate alloy. Preliminary studies on iron-iridium indicate not only that the segregation effects occur in this system, but that it is possible to obtain catalysts with the high activity associated with iridium but displaying the strong selectivity associated with the much less active iron. In this study, iron-iridium and iron- palladium catalysts are studied using Mossbauer spectroscopy, X-ray diffraction, electron microscopy, calorimetry, and reaction probes. The initial reaction probe is 1-butene hydrogenation/isomerization. This work is exciting for its practical implications. Adoption of automotive emissions standards by the European Community has placed a great strain on the world supply of noble metals, and a major objective of much research is to develop means of controlling emission that do not rely on these very expensive and scarce materials. This approach does not eliminate the need for noble metals, but it greatly reduces the amounts required, perhaps by as much as 80%, replacing it with readily available iron. The work is also significant for insights into alloy formation and stability.