Understanding and predicting the performance of metal exchanged SSZ-13 zeolite in the conversion of methane to methanol

目前，地球仪正在开采大量的页岩气储量。页岩气主要是甲烷，难以运输，价值相对较低。将甲烷转化为更高价值的产品，如甲醇，需要新的和改进的催化方法。甲醇是一种平台化学品，现有技术可将其转化为各种有用的重要产品。金属交换沸石是一类显示出作为将甲烷转化为甲醇的催化剂的巨大前景的材料。然而，这些催化剂是如何工作的还没有很好的理解。此外，它们的催化性能取决于许多难以优化的复杂参数。在这个项目中，威斯康星州大学的Mavrikakis博士正在使用理论和实验来了解一种特定的沸石结构，称为SSZ-13，用于将甲烷转化为甲醇的性能。他的工作是开发沸石合成条件和SSZ-13的化学组成之间的相关性，以及其催化性能和反应条件之间的相关性。所获得的见解被用于设计实验合成方案，以生产理想的沸石催化剂和甲烷转化为甲醇的反应条件。在这个项目中，Mavrikakis博士向公众介绍了理论建模在基础和工业研究与实践中的重要性。Mavrikakis博士还教育本科生如何向初中和高中生传播科学，并为本科生提供实习机会，让他们在他的小组中进行研究。在化学部化学催化计划的资助下，威斯康星州-麦迪逊大学的Mavrikakis博士正在应用一种综合的理论/实验方法，用于理解使用过渡金属交换的SSZ-13沸石将甲烷转化为甲醇的基本原理。这包括：（i）沸石合成的第一原理建模，通过开发合成参数（例如模板和存在的离子的特性）与所获得的沸石结构（例如局部Al分布和缺陷密度）之间的相关性;（ii）不同过渡金属相图的从头计算（铜，铁，钴，镍）和类型的活性位点的广泛的操作条件下，和（iii）最稳定的活性催化位点的反应途径的计算。在随后的步骤中，该信息被用于开发实验合成、元素组成和反应条件的方案，以使用于将甲烷转化为甲醇的理想金属交换SSZ-13沸石的性能最大化。与此同时，Mavrikakis博士的团队与威斯康星州化学教育研究所合作，正在开发模块，教授本科生和中学生如何在分子水平上思考，从而产生新的强大技术。此外，P.I.参加了威斯康星大学麦迪逊分校的本科生研究经验项目，该项目为本科生研究人员提供实践研究经验，重点关注女性学生和代表性不足的学生群体。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Vast reserves of shale gas are now being accessed around the globe. Shale gas is mostly methane, which is difficult to transport and of relatively low value. The conversion of methane into higher value products, such as methanol, requires new and improved catalytic processes. Methanol is a platform chemical, with existing technologies for transforming it into a variety of useful, important products. Metal exchanged zeolites are a class of materials showing great promise as catalysts for transforming methane to methanol. However, how these catalysts work is not yet well-understood. Further, their catalytic performance depends on many complex parameters which are difficult to optimize. In this project, Dr. Mavrikakis of the University of Wisconsin is using both theory and experiments to understand the performance of one specific zeolite structure, known as SSZ-13, for the conversion of methane to methanol. His work is developing a correlation between zeolite synthesis conditions and the resulting chemical composition of SSZ-13, and between its catalytic performance and reaction conditions. The insights gained are being used to design experimental synthesis protocol to produce the ideal zeolite catalyst and reaction conditions for methane conversion to methanol. During this project Dr. Mavrikakis is informing the public about the importance of theoretical modeling in fundamental and industrial research and practice. Dr. Mavrikakis is also educating undergraduate students about communicating science to middle school and high school students, as well as providing internships to undergraduate students to conduct research in his group.With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. Mavrikakis at the University of Wisconsin - Madison is applying a combined theoretical/experimental approach for understanding the fundamentals of converting methane to methanol using transition metal exchanged SSZ-13 zeolite. This includes: (i) first-principles modeling of zeolite synthesis through the development of correlations between synthesis parameters, such as the identity of template and ions present, and the obtained zeolite structure, such as the local Al distribution and defect density; (ii) the ab-initio calculation of phase diagrams for different transition metals (Cu, Fe, Co, Ni) and types of active sites for a wide range of operating conditions, and (iii) the calculation of reaction pathways for the most stable active catalytic sites. In a subsequent step, this information is being used to develop a protocol for the experimental synthesis, elemental composition and reaction conditions for maximized performance of the ideal metal exchanged SSZ-13 zeolite for the conversion of methane to methanol. In parallel, and in collaboration with the Wisconsin Institute for Chemical Education, Dr. Mavrikakis' group is developing modules to teach undergraduate and middle school students how thinking at the molecular level can lead to new powerful technologies. Furthermore, the P.I. is participating in the Research Experience for Undergraduates program at UW Madison, which is providing hands-on research experiences to undergraduate researchers with a focus on female students and students from underrepresented groups.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.