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。该项目推进了催化加工技术，在位于生产井或附近的小工厂将甲烷升级为更高价值的化学品，从而避免燃烧或昂贵的天然气管道运输。目前用于该工艺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。这项研究结合了实验和理论方法，以更好地了解限制当前催化剂性能的因素，并利用这些知识来指导改进的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与高效、低成本和低环境影响的碳氢资源利用相关技术的培训，同时促进与以少数民族为主的学校的接触，以吸引K-12学生进入STEM领域。该项目的目标是甲烷脱氢芳构化(MDA)，这是一种将甲烷直接转化为苯和氢气的途径。具体来说，该项目的重点是ZSM-5负载的钼(Mo)催化剂。研究人员之前的工作揭示了ZSM-5负载的氧化钼前驱体被活化形成碳化钼物种的特定过程对催化行为有很大影响。因此，Mo-C-载体相互作用对芳烃的稳定生成起着关键作用。为了进一步研究这些相互作用，将制备活性金属只存在于沸石外表面或沸石通道内的模型催化剂，并用一套实验和计算工具对其进行评估。钼物种的结构、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)的原位和操作数实验来监测。实验数据将与密度泛函理论计算相结合，以加深对催化剂结构-活性关系的了解，以及整个丙二醛催化循环(活化、反应、失活、再生)所涉及的反应途径。动力学测试、原位结构表征和理论计算相结合，将确定丙二醛的反应和失活途径，为催化剂的合理设计提供依据。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，允许K-12学生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3-D图像进行交互。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.