Integrated Experimental and Theoretical Endeavor for Fundamental Understanding of Processes in Methane Dehydroaromatization

西德克萨斯二叠纪盆地拥有数万亿立方英尺的天然气资源，主要由甲烷组成，这构成了数十亿美元的经济机会，可以将这种低碳化石燃料升级为更高价值的燃料和化学品。该项目推进了催化处理技术，将位于生产井附近或附近的小型工厂的甲烷升级为高价值的化学品，从而避免了燃烧或昂贵的天然气管道运输。目前在该工艺中使用的催化剂不能满足使该工艺在经济上可行所必需的活性和稳定性要求。该研究将实验和理论方法相结合，以更好地了解限制当前催化剂性能的因素，并利用这些知识指导改进催化剂和加工方案的设计。该项目还促进对研究生和本科生进行高效、低成本和低环境影响碳氢化合物资源利用相关技术的培训，同时促进与少数民族学校的联系，以吸引K-12学生进入STEM领域。该项目针对甲烷脱氢芳构化（MDA），这是甲烷直接转化为苯和氢的途径。具体而言，该项目侧重于zsm -5负载的钼（Mo）催化剂。研究人员先前的工作表明，zsm -5负载的Mo氧化物前驱体被激活形成Mo碳化物的特定过程强烈影响催化行为。因此，mo - c -支持相互作用在实现芳烃的稳定形成中起着关键作用。为了进一步研究这些相互作用，活性金属只存在于外表面或沸石通道内的模型催化剂将被制备并通过一套实验和计算工具进行评估。Mo物种的结构、位置和演化将通过使用先进的表征技术（包括x射线吸收和高分辨率粉末衍射）进行原位和操作实验来监测。实验数据将与密度泛函理论计算相结合，以提高对催化剂结构-活性关系的认识，以及完整的MDA催化循环（活化、反应、失活、再生）中涉及的反应途径。将动力学试验、原位结构表征和理论计算相结合，确定丙二醛的反应和失活途径，为合理设计催化剂提供依据。除了研究工作之外，研究人员还将开发一种新的虚拟现实（VR）技术模块，使K-12学生能够沉浸在催化剂结构中，并允许他们直接与催化过程中涉及的分子的动态3d图像进行交互。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The West Texas Permian Basin holds trillions of cubic feet of natural gas resources predominantly comprised of methane, which constitutes an economic opportunity in the billions of dollars to upgrade this low-carbon fossil fuel to higher-value fuels and chemicals. The project advances catalytic processing technology that upgrades methane to higher-value chemicals in small plants located at or near the production wells, thus avoiding flaring or costly gas pipeline transport. The catalysts currently employed in this process do not fulfill the activity and stability requirements necessary to make the process economically viable. The study integrates experimental and theoretical methods to better understand the factors limiting current catalyst performance, and uses that knowledge to guide the design of improved catalysts and processing schemes. The project also promotes training of graduate and undergraduate students in technologies related to efficient, cost-effective, and low environmental impact utilization of hydrocarbon resources, while promoting outreach to predominantly minority schools to attract K-12 students to STEM fields.This project targets methane dehydroaromatization (MDA) which constitutes a path for the direct conversion of methane to benzene and hydrogen. Specifically, the project focuses on ZSM-5-supported molybdenum (Mo) catalysts. Previous work by the investigators has revealed that the specific processes by which a ZSM-5-supported Mo oxide precursor is activated to form Mo carbide species strongly affects the catalytic behavior. Thus, Mo-C-support interactions play a pivotal role in achieving the stable formation of aromatics. To further investigate those interactions, model catalysts, with active metals existing only on either the outer surface or within the zeolite channels, will be prepared and evaluated by a suite of experimental and computational tools. The structure, location, and evolution of the Mo species will be monitored by in situ and operando experiments using advanced characterization techniques, including X-ray absorption and high-resolution powder diffraction. The experimental data will be combined with density functional theory calculations to advance knowledge with respect to the structure-activity relationship of the catalysts and the reaction pathways involved in the complete MDA catalytic cycle (activation, reaction, deactivation, regeneration). The combination of kinetic tests, in situ structural characterization, and theoretical calculations will result in the determination of the reaction and deactivation pathways of MDA and will provide the basis for the rational design of catalysts. Beyond the research efforts, the investigators will develop a novel virtual reality (VR) technology module that will allow K-12 students to immerse themselves into a catalyst structure and allow them to directly interact with dynamic 3-D images of the molecules involved in a catalytic process.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.