First-Principles Design of Coke-Resistant Dehydrogenation Catalysts for Valorization of Light Hydrocarbon Feedstocks

该项目将研究用于将轻烃气体转化为高价值产品的催化剂中毒机理。具体来说，它将解决焦炭形成的问题——碳氢化合物在催化剂表面分解形成碳质沉积物，使催化剂失去活性的过程。机理的理解将从理论预测和实验测量中得到，并将用于预测、合成和评估新的催化剂配方，这些配方可以抵抗通过焦炭形成的失活。为了确保与美国页岩资源相关的巨大天然气储量的有效利用，需要无毒脱氢催化剂。高效、耐用和具有经济吸引力的催化剂对于将轻质气体升级为对经济的能源和化学部门有价值的原料至关重要。该项目将对表面物质和pt合金脱氢催化剂之间的相互作用有一个基本的了解，这种相互作用导致了它们对烯烃和轻质烷烃高温脱氢过程中的焦炭沉积的选择性。烯烃的形成已被研究，而焦炭的形成机理尚不清楚。密度泛函理论（DFT）将用于生成烷烃解离形成碳质表面物种的势能面和动力学激活势垒，从而揭示该机制如何受到催化剂的电子和几何结构的影响。通过分析沉积在催化剂表面的分子碎片，进行相应的实验研究，以了解结焦机理。从DFT和实验表征的见解将被用于设计新的催化剂合金结构和成分，增强抗失活能力。预测的设计将通过合成新型催化剂和测试其催化性能进行实验验证。轻烷烃，如乙烷和丙烷，是碳氢化合物加工的副产品，是天然天然气的少数成分，没有什么商业价值，有时只是为了它们的热值而燃烧。这些碳氢化合物脱氢生成相应的烯烃将产生高价值的中间体，特别是作为化学和聚合物前体的吸引力。这项工作的结果将有助于通过本科化学工程课程和从不同的罗格斯大学本科生群体中招募研究人员来为该项目做出贡献，从而建立一个多样化的未来化学工业劳动力。

The project will study the mechanism of poisoning of catalysts used to convert light hydrocarbon gases to higher value products. Specifically it will address coke formation - the process by which the hydrocarbons break down on the surface of the catalysts to form carbonaceous deposits that deactivate the catalyst. Mechanistic understanding will be derived from both theoretical predictions and experimental measurements, and will be used to predict, synthesize, and evaluate new catalyst formulations that are resistant to deactivation via coke formation. Poison-resistant dehydrogenation catalysts are needed to ensure effective utilization of the huge gas reserves associated with the Nation's shale resources. Efficient, durable, and economically attractive catalysts are essential for upgrading the light-gases to feedstocks of value to the energy and chemical sectors of the economy.The project will develop a fundamental understanding of the interaction between surface species and Pt-alloy dehydrogenation catalysts that give rise to their selectivity towards alkenes and for coke deposition during the high-temperature dehydrogenation of light alkanes. While the formation of the alkene has been studied, the mechanism of coke formation is unknown. Density Functional Theory (DFT) will be used to generate potential energy surfaces and kinetic activation barriers for the dissociation of alkanes to form carbonaceous surface species, thereby revealing how this mechanism is influenced by the electronic and geometric structure of the catalyst. Corresponding experimental studies will be carried out to understand the coking mechanism via analysis of the molecular fragments deposited on the catalyst surface. The insights from DFT and experimental characterization will be exploited to design new catalyst alloy structures and compositions with enhanced resistance to deactivation. Predicted designs will be experimentally validated by synthesizing the novel catalysts and testing their catalytic performance. Light alkanes, such as ethane and propane, produced as byproducts of hydrocarbon processing, and found naturally as minority components of natural gas, have little commercial value, and are sometime flared or burned only for their caloric value. Dehydrogenation of these hydrocarbons to their corresponding alkenes would produce higher-value intermediates especially attractive as chemical and polymer precursors. The results from this work will serve to build a diverse future chemical industry workforce through undergraduate chemical engineering curricula and recruiting of researchers from the diverse Rutgers undergraduate student body to contribute to the project.