GOALI: A Scientific Synthesis of Bimetallic Catalysts

制备负载型金属催化剂最常见的方法是用溶解金属络合物的水溶液浸渍多孔氧化物或碳。大多数制备的目标是将沉积的前体(通常是配位络合物)转化为牢牢固定在高表面积载体上的小金属颗粒。对于给定数量的金属，金属颗粒越小，产生的催化活性中心就越多。在促进型或双金属催化剂中，目标通常是最大限度地使金属和促进剂或两种金属接触。如何有效地实现这一点是学术界和工业界许多研究的主题。在许多情况下，这些准备步骤被认为是艺术。南卡罗来纳大学的John Regalbuto教授一直在有效地研究负载型金属催化剂浸渍过程中出现的基本现象，努力将催化剂制备艺术转化为一门科学。在过去得到美国国家科学基金会的支持下，他的研究小组描述了在浸渍过程中贵金属和贱金属配位络合物在许多氧化物和碳上的吸收，这是一种简单的静电机制，导致了前体-表面相互作用最强的最佳pH。对这些单金属催化剂的其他制备步骤的基本方面也进行了研究。在这项提议中，强静电吸附方法将应用于最复杂但影响最大的制备方法-双金属催化剂。雷加尔布托假定，这种方法将产生前所未有的双金属催化剂的形态控制使用真正的，高比表面积载体，使用常见的，商业上可获得的金属前体。具体地说，他假设可以通过选择性地将一种金属前体络合物吸附到第二种金属的氧化物上来制备核壳结构，并且在较低的还原温度下将保持核壳结构，而在较高温度下将形成合金。科学方法的另一种替代应用预测，通过在单一吸附步骤中共吸附金属络合物，可以通过低温还原制备均质合金。希望这项工作的成功示范将导致对双金属催化剂制备的理解和实践的转变。潜在的科学影响极其广泛，影响到使用双金属催化剂的化学工业的方方面面。有了这个目标，这个奖项就是一个守门员奖。Regalbuto与位于英国松宁的强生马泰技术中心合作，后者是贵金属催化剂制造的世界领先公司。JMTC和南卡罗来纳大学将首次对各种贵金属氧化物进行零电荷点测量和吸附测量。在战略上，与工业界的伙伴关系将使人们能够获得吸附性能基础研究所需的大量贵金属氧化物。该项目工作是专门为REU学生制定的；这项工作将相对容易进行，令人兴奋，并将在同行评议的出版物和会议演讲中引起注意。此外，PI将与南加州大学提供的全面的外展和多样性项目组合相结合：路易斯·斯托克斯少数群体参与联盟、SC少数群体参与联盟和东南研究生教育联盟。

#1160036RegalbutoThe most common method of preparing supported metal catalysts begins by impregnating a porous oxide or carbon with an aqueous solution of dissolved metal complexes. The goal of most preparations is to convert the deposited precursor, often a coordination complex, into small metal particles firmly anchored onto the high surface area support. For a given amount of metal, the smaller the metal particles, the more catalytically active sites are created. In promoted or bimetallic catalysts, the goal is normally to maximize contact of the metal and promoter, or the two metals. How to achieve this effectively is the subject of many studies, both academic and industrial.In many cases these preparation steps are considered to be art. Professor John Regalbuto of the University of South Carolina has been effectively studying the fundamental phenomena that occur during supported metal catalyst impregnation, striving to transform the art of catalyst preparation into a science. With past support from NSF his research group has described the uptake of noble and base metal coordination complexes over many oxides and carbons during impregnation in terms of a simple electrostatic mechanism leading to an optimal pH at which the precursor-surface interaction is strongest. Fundamental aspects of the other preparation steps of these monometallic catalysts have also been studied. In this proposal, the strong electrostatic adsorption approach will be applied to the most complicated but highest impact preparations - bimetallic catalysts. Regalbuto postulates that this approach will yield unprecedented control of the morphology of bimetallic catalysts prepared with real, high surface area supports using common, commercially available metal precursors. Specifically, he hypothesizes that core-shell morphologies can be prepared by selectively adsorbing one metal precursor complex onto the oxide form of a second metal, and that core-shell morphology will be retained with low reduction temperatures and alloys will form at higher temperatures. Another alternative application of the science approach predicts that homogeneous alloys can be prepared with low temperature reductions by coadsorbing metal complexes in a single adsorption step.It is hoped that successful demonstrations of the proposed work will lead to a transformation in the understanding and practice of bimetallic catalyst preparation. The potential scientific impact is extremely broad, affecting all facets of the chemical industry which employ bimetallic catalysts. With that target, this award is a GOALI award. Regalbuto has teamed with the Johnson Matthey Technical Centre in Sonning, UK, a world leading company in noble metal catalyst manufacture. Measurements of point of zero charge and adsorption surveys over a wide range of noble metal oxides will be made for the first time at JMTC as well as at the University of South Carolina. Strategically, the partnership with industry will allow access to the copious amounts of noble metal oxides needed for the fundamental studies of adsorption properties.The project work has been formulated specifically for REU students; this work will be relatively easy to undertake, exciting to do, and will get noticed in peer reviewed publications and conference presentations. In addition the PI will tie into the comprehensive portfolio of outreach and diversity programs offered at USC: the Louis Stokes Alliance for Minority Participation, the SC Alliance for Minority Participation, and the South East Alliance for Graduate Education.