CAREER: Catalytic Resonance-Enhanced Activation of Hydrocarbon Resources

要利用最近丰富的美国页岩气资源作为化工生产原料，需要使用催化升级战略。与原料和产品的化学成分和地理分布有关的限制要求开发能够利用这些新资源的创新催化战略。在具有成本竞争力的可再生电力的持续增长的推动下，使用电化学策略来激活碳氢资源提供了一个独特的机会，通过避免等同于热驱动的化学转化的高压和温度来减少对环境的影响和化学制造的成本。此外，电化学方法更能抵御对传统化学品制造供应链构成弹性和安全威胁的重大破坏事件。因此，在这一研究计划中开发电驱动化学反应策略具有重大的变革潜力。然而，目前碳氢资源的直接电化学催化改质受到反应速度慢和目标产物选择性差的限制。这项研究将促进催化共振的发展，即催化剂的能量被及时调节，以最大限度地提高反应速度和对目标产物的选择性。这项研究将把可持续化学转化、可再生能源和催化动力学的概念整合到一个教育计划中，让马萨诸塞州大学和周边地区的学生都参与进来。将通过开发在线教育内容、使用简单有效的教学技术来交流与能源有关的应用背后的基础科学，扩大外联工作的影响。这项研究将侧重于发展对碳氢化合物电化学氧化成增值含氧物的催化共振的基本理解。虽然很容易获得可再生且成本效益高的能源来推动电化学反应，但与碳氢化合物(例如，烷烃、烯烃)的电化学氧化有关的催化剂周转速度限制了这种方法。金属催化剂表现出明显的电催化活性，但由于碳氢化合物过度氧化为二氧化碳而成为一种不受欢迎的产物，因此对部分氧化产物缺乏选择性。在稳态条件下，对催化活性和选择性的挑战有着相似的根源：平衡必要的吸附覆盖率、动力学推动力以及催化循环中涉及的法拉第和非法拉第基本步骤的组合。催化工作电极的受控能量振荡分离了速度决定因素，允许它们通过进入在静态条件下无法维持的非平衡状态而独立调整。虽然这项研究的重点是碳氢化合物的氧化，但这项工作将发展所需的理解和能力，以将催化共振的概念扩展到其他重要的化学转化。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。

Leveraging the recent abundance of U.S. shale gas resources as a chemical production feedstock requires the use of catalytic upgrading strategies. Constraints related to chemical composition and geographical distribution of both the feedstocks and products require the development of innovative catalytic strategies that can take advantage of these new resources. Motivated by the continuous growth of cost-competitive renewable electric power, the use of electrochemical strategies to enable the activation of hydrocarbon resources provides a unique opportunity to reduce the environmental impact and cost of chemical manufacturing by avoiding the high pressures and temperatures synonymous with thermally driven chemical transformations. Furthermore, the electrochemical approach is more resistant to major disruption events that pose resilience and safety threats in traditional chemical manufacturing supply chains. Therefore, the development of electrically driven chemical reaction strategies in this research program has significant transformative potential. Direct electrochemical catalytic upgrading of hydrocarbon resources, however, currently is limited by both slow reaction rates and poor selectivity to desired products. This study will advance the development of catalytic resonance, whereby the energetics of a catalyst is modulated in time to maximize the reaction rate and selectivity towards the desired product. This study will integrate concepts of sustainable chemical transformation, renewable energy sources, and catalytic kinetics into an educational plan that will engage students both at UMass and the surrounding area. The impact of outreach efforts will be expanded by developing educational online content, using simple and effective teaching techniques to communicate the fundamental science behind energy related applications.This study will focus on developing a fundamental understanding of catalytic resonance for the electrochemical oxidation of hydrocarbons into value-added oxygenates. While renewable and cost-effective energy to drive the electrochemical reactions is readily available, the rate of catalytic turnover associated with the electrochemical oxidation of hydrocarbons (e.g., alkanes, alkenes) limits the approach. Metal catalysts that do exhibit appreciable electrocatalytic activity are plagued by the lack of selectivity to partial oxidation products due to the over-oxidation of hydrocarbons into carbon dioxide as an undesirable product. Under steady-state conditions, the challenges to catalytic activity and selectivity share a similar origin: balancing the necessary adsorbate coverages, kinetic driving force, and the combination of faradaic and non-faradaic elementary steps involved in the catalytic cycle. Controlled energetic oscillations of the catalytic working electrode decouples the rate-determining factors, allowing for their independent tuning by accessing non-equilibrium states that cannot be sustained under static conditions. While this study will focus on hydrocarbon oxidation, the work will develop the understanding and capabilities needed for extending the concept of catalytic resonance to other important chemical transformations.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.