Collaborative Research: Correlating Molecular Structure and Activity in Boron-containing ODH Catalysts

随着世界人口的增长，对由乙烯和丙烯等基本化学物质制成的消费品的需求也在增加。该项目的重点是发现以天然气为原料生产这些化学构件的节能催化剂，同时尽量减少产生不需要的副产品，如二氧化碳。研究人员的初步研究已经显示出含硼催化剂的非凡前景，但要进一步提高催化剂的性能和耐久性，还需要更深入的、原子水平的理解。该项目将结合新的催化剂合成方案、最先进的固态核磁共振成像和计算方法来获得所需的原子水平的理解，并利用这些见解来设计改进的催化剂。这项研究将通过将我国巨大的页岩气资源有效转化为增值燃料和化学品的潜力，支持美国的清洁能源安全。轻烷烃的氧化脱氢（ODH）是一种很有前途的替代生产重要的化学构件。然而，尽管经过了几十年的研究，高选择性催化剂仍然是难以捉摸的，因为过度氧化是一个容易的和热力学有利的过程。研究小组最近的研究表明，含硼催化剂（hBN、BNNT、WB等）对轻烷烃的ODH具有高度选择性。对于丙烷ODH，在转化率为20%的情况下，丙烯选择性高达80%，而对于最先进的钒基催化剂，在丙烷转化率为10%的情况下，丙烯选择性为60%。鉴于最近这类材料作为ODH催化剂的发现，有许多关于活性位点及其形成的基本问题需要回答。受控合成、最先进的固态核磁共振（SSNMR）光谱和计算模型将用于深入了解催化活性位点，并建立含硼ODH催化剂的结构-性能关系。这项工作将有助于在分子水平上理解一个具有工业重要性的复杂问题。我们的多学科方法包括合成，SSNMR表征，催化测试和计算建模，将训练参与的学生使用来自不同领域的信息来开发复杂系统的详细图片。此外，这项工作的协作性质将帮助学生成长为研究团队中富有成效的成员。除了目标反应之外，该研究将对更广泛的催化界具有价值，因为它具有广义的催化见解和开发的表征非均相材料的方法。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。

As the world population grows, the demand for consumer goods, which are made from building-block chemicals such as ethylene and propylene, increases. The project focuses on discovery of energy-efficient catalysts for the production of these chemical building-blocks from natural gas with minimal generation of undesired by-products such as carbon dioxide. Preliminary studies by the investigators have shown exceptional promise of boron-containing catalysts, but deeper, atomic-level understanding is needed to further improve the catalyst performance and durability. The project will utilize a combination of new catalyst synthesis protocols, state-of-the-art solid-state nuclear magnetic resonance imaging, and computational methods to obtain the needed atomic-level understanding, and use that insight to design improved catalysts. The research will support U.S. clean-energy security through its potential for the efficient conversion of our nation's vast shale gas resources to value-added fuels and chemicals. Oxidative Dehydrogenation (ODH) of light alkanes is a promising alternative for the production of important chemical building blocks. However, despite decades of research, a highly selective catalyst has remained elusive, as over-oxidation is a facile and thermodynamically favored process. Recent studies by the lead investigator's group has demonstrated that boron-containing catalysts (hBN, BNNT, WB, among others) are highly selective catalysts for the ODH of light alkanes. For propane ODH, propylene selectivity as high as 80% can be obtained up to 20% conversion, compared to 60% propylene selectivity at 10% propane conversion for the state-of-the-art vanadium oxide-based catalyst. Given the recent discovery of this class of materials as ODH catalysts, there are many fundamental questions that need to be answered regarding the active sites and their formation. Controlled synthesis, state-of-the-art solid-state NMR (SSNMR) spectroscopy, and computational modelling will be utilized to gain insights into the catalytically active site(s) and build up a structure-performance relationship for boron-containing ODH catalysts. The work will contribute to a molecular-level understanding of a complex problem that is of industrial importance. Our multidisciplinary approach comprised of synthesis, SSNMR characterization, catalytic testing, and computational modelling will train the participating students to use information from a variety of fields to develop a detailed picture of a complex system. Additionally, the collaborative nature of this work will help the students grow as productive members of a research team. Beyond the targeted reactions, the study will be of value to the broader catalysis community because of the generalized catalytic insights and the methods developed for characterization of heterogeneous materials.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.