CAREER:Fundamental Studies of the Roles and Interactions of Disparate Metals in p-d Alloy Catalysts

职业：不同金属在 p-d 合金催化剂中的作用和相互作用的基础研究

• 批准号: 0747646
• 负责人: Randall Meyer
• 金额: $ 40.15万
• 依托单位: University of Illinois at Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0747646&HistoricalAwards=false
• 关键词: CAREER; Fundamental; Studies; Roles; Interactions

0747646MeyerBimetallic catalysts have long been of scientific interest due to the intriguing possibilities that exist with regard to tuning the properties of the catalyst by varying the composition and creating unique local ensembles (active sites). Norskov and coworkers have greatly contributed to our understanding of catalysis through an analysis of the behavior of d-band transition metals. Norskov et al have shown that simple relationships hold equally for transition metals and their alloys and that the average d-band filling of the metal atoms in surface layer(s) acts a predictor of adsorption strength. However, there are a few catalyst systems of considerable importance (e. g. PtSn catalysts for catalytic reforming) where a d-band transition metal is alloyed with a non-transition metal (a metal with some occupancy in p-orbitals in the valence band) and the simple picture of examining the d-band center as a universal predictor seems insufficient. Therefore, this proposal through a combined theoretical/experimental approach will attempt to develop simple rules which could describe the adsorption behavior of p-d alloys (p-electron metals alloyed with d-band metals) in a similar way as has been previously established by Norskov et al for d-band transition metal alloys. Intellectual Merit The importance of this work is to extend established correlations which describe d-transition metal alloys to a new class of catalysts: alloys involving a d-band transition metal (e.g Pt) and one involving a main group metal (e.g. Sn or Zn). The work will be performed in a collaborative effort between experiment and theory utilizing multiple techniques. A variety of p-d alloy catalysts will be synthesized, and extensively characterized using EXAFS, in situ-XPS, and STEM-EELS. Following their characterization the catalyst will be tested under realistic operating conditions using a traditional microreactor in an effort to link the composition and structure of our materials to their reactivity (and selectivity) for two reactions of considerable importance: water gas shift and propane dehydrogenation. Density Functional Theory studies will examine the electronic structure of these materials and their stability under reaction conditions. Finally theory will be called upon to improve our understanding of the mechanism and thereby aid our design of new catalysts. Broader Impact This study is of a very general nature and as such may ultimately lead toward ?rules of thumb? in catalyst design as Norskov?s seminal work regarding d-band theory which this work hopes to augment and emulate. Multiple collaborative investigators will work together with the students on this project, each with a unique research perspective (partially as a product of the institutions with which they are affiliated). Therefore the student will gain an appreciation of research at industrial (Dr. Jeff Miller of BP), governmental (Dr. Jeremy Kropf of Argonne National Laboratory) and academic institutions (Professor Robert Klie and John Regalbuto of the University of Illinois at Chicago; Prof. Fabio Ribeiro of Purdue University). The PI intends to make considerable use general user facilities at the Advanced Photon Source (APS) at Argonne National Lab (for EXAFS) and the Advanced Light Source (ALS) at Lawrence Berkeley Labs (for high pressure XPS) which will expose the students to a large variety of research environments as well as a number of synergistic techniques. This work involves practical examples which illustrate the usefulness of undergraduate level chemical thermodynamics and reaction kinetics which can be incorporated into existing courses taught by the PI. The test reactions of interest for these catalysts involve both traditional hydrocarbon catalysis and hydrogen production, a reaction of increasing potential importance to our energy future. These examples will be integrated in the appropriate context to the department?s new introductory course for first year students in chemical engineering. Finally, it is hoped to extend this even further to high school level through interaction with the Illinois Math and Science Academy.

0747646迈耶双金属催化剂长期以来一直受到科学界的关注，因为通过改变组成和创造独特的局部集合（活性位点）来调节催化剂的性能存在着令人感兴趣的可能性。Norskov和他的同事通过分析d-带过渡金属的行为极大地促进了我们对催化的理解。Norskov等人已经表明，简单的关系同样适用于过渡金属及其合金，并且表面层中金属原子的平均d带填充可以预测吸附强度。然而，存在一些相当重要的催化剂体系（例如，G.用于催化重整的PtSn催化剂），其中d带过渡金属与非过渡金属（在价带中的p轨道中具有一些占据的金属）形成合金，并且检查d带中心作为通用预测器的简单图片似乎是不够的。因此，本提案将通过理论/实验相结合的方法，试图开发简单的规则，可以描述的吸附行为的p-d合金（p-电子金属合金与d-带金属），以类似的方式已经建立了由Norskov等人的d-带过渡金属合金。这项工作的重要性是将已建立的描述d-过渡金属合金的相关性扩展到一类新的催化剂：涉及d-带过渡金属（例如Pt）的合金和涉及主族金属（例如Sn或Zn）的合金。这项工作将利用多种技术在实验和理论之间进行合作。将合成各种p-d合金催化剂，并使用EXAFS，原位XPS和STEM-EELS进行广泛表征。在其表征之后，将使用传统的微型反应器在实际操作条件下对催化剂进行测试，以努力将我们材料的组成和结构与其对两个相当重要的反应的反应性（和选择性）联系起来：水煤气变换和丙烷脱氢。密度泛函理论研究将检查这些材料的电子结构及其在反应条件下的稳定性。最后，理论将被要求提高我们的机制的理解，从而帮助我们设计新的催化剂。更广泛的影响这项研究是一个非常普遍的性质，因此可能最终导致？经验法则在催化剂设计方面有什么贡献吗的开创性工作，关于d波段理论，这项工作希望加强和模仿。多个合作研究人员将与学生一起参与这个项目，每个人都有一个独特的研究视角（部分作为他们所属机构的产品）。因此，学生将获得在工业（BP的Jeff米勒博士），政府（阿贡国家实验室的Jeremy Kropf博士）和学术机构（芝加哥伊利诺伊大学的Robert Klie和John Regalbuto教授;普渡大学的Fabio Ribeiro教授）的研究的赞赏。PI打算大量使用阿贡国家实验室（用于EXAFS）的高级光子源（APS）和劳伦斯伯克利实验室（用于高压XPS）的高级光源（ALS）的一般用户设施，这将使学生接触到各种各样的研究环境以及一些协同技术。这项工作涉及实际的例子，说明本科水平的化学热力学和反应动力学，可以纳入现有的课程教授的PI的有用性。对这些催化剂感兴趣的测试反应涉及传统的烃催化和制氢，这是一种对我们的能源未来越来越重要的反应。这些例子将在适当的背景下整合到该部门？为化学工程专业一年级学生开设的新入门课程。最后，希望通过与伊利诺伊州数学和科学学院的互动，将这一点进一步扩展到高中水平。