EAGER: Periodic Binding Energy Modulation for Electrochemical Systems

催化剂是一种加速化学反应的材料，从而降低化学制造过程的成本、能源消耗和资本设备需求。大多数催化剂研究的重点是发现加速目标反应的最佳材料组合。然而，就材料本身加速反应的程度而言，存在着根本的限制。该研究将通过在反应事件的时间尺度上对催化剂的操作条件引入动态扰动来绕过这些材料的限制。这一全新的概念将在水分解反应中得到证明——水分解反应是利用可再生能源产生氢气的重要反应。初步的理论分析表明，通过动态扰动可以将反应速率提高几个数量级，同时也为更便宜的催化剂用于广泛的化学反应打开了大门。材料的催化活性是由关键反应中间体的结合能决定的，通过能量缩放关系来描述，它预测了催化活性的最大值-以著名的萨巴蒂尔原理为特征-仅通过材料设计即可实现。水的电化学分解产生可再生氢受到这一限制，其中析氢反应的速率由氢的结合能决定。在贵金属催化剂上发现了最佳的氢结合能，这一事实进一步加剧了这个问题，给本已具有经济挑战性的工艺带来了压力。这项研究将调查在多大程度上应用周期振荡的应用电位，在周转事件的时间尺度上，可以改变氢在电极表面的结合能量。在不断振荡的应用电位下操作催化剂，其中反应中间体的结合能不断变化，允许单一催化剂以周期性的方式模拟多种材料的性能。这将使催化剂的设计突破目前由缩放关系所施加的限制，达到前所未有的催化活性水平。实现这种革命性的操作方法目前受到我们在反应条件下精确改变催化材料结合能的实验能力的限制。具体而言，该项目将探索在标准电化学电池中使用交流电位进行有效的水分解。该实验设计还将用于研究耦合热催化与作为结合能调制平台的电化学系统。该方法可能适用于广泛的具有商业和环境重要性的催化反应。动态催化的概念也将通过一门由首席研究员开发的选修课程介绍给研究生。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。

Catalysts are materials that accelerate chemical reactions and thereby reduce the cost, energy consumption, and capital equipment demands of chemical manufacturing processes. Most catalyst research focuses on discovering combinations of materials that are optimal for accelerating the targeted reaction. Fundamental limitations exist, however, regarding the extent to which materials alone can accelerate reactions. The study will side-step such materials limitations by introducing dynamic perturbations to the catalyst's operating conditions at the timescale of reaction events. The radically new concept will be demonstrated on the water splitting reaction - an important reaction for generating hydrogen by renewable means. Preliminary theoretical analysis has suggested that reaction rates can be increased by orders of magnitude via the dynamic perturbations, while also opening the door to less expensive catalysts for a wide range of chemical reactions. The catalytic activity of materials is dictated by the binding energetics of key reaction intermediates, described through energy scaling relationships, which predicts a maximum in the catalytic activity - characterized by the well-known Sabatier principle - achievable through only material design. The electrochemical splitting of water to produce renewable hydrogen suffers from this limitation, where rates of hydrogen evolution reactions are dictated by the binding energy of hydrogen. The problem is further exacerbated by the fact that optimal hydrogen binding energies are found on precious metal catalysts, placing strain on an already economically challenging process. The study will investigate the extent to which the application of periodic oscillations in applied potential, on the timescale of turnover events, can alter the binding energetics of hydrogen on the electrode surface. Operating catalysts under a constantly oscillating applied potential, where binding energetics of reaction intermediates are constantly changing, allows a single catalyst to mimic the performance of multiple materials in a periodic fashion. This will allow for the design of catalysts that break past the current limitations imposed by scaling relationships, to reach unprecedented levels of catalytic activity. Implementing this transformative method of operation is currently limited by our experimental ability to alter binding energetics on catalytic materials with precision under reaction conditions. Specifically, the project will explore the use of alternating potentials in standard electrochemical cells for efficient water splitting. This experimental design will also be used to investigate coupling thermocatalysis with electrochemical systems that serve as a binding energy modulation platform. The approach is potentially applicable to a broad range of catalytic reactions of commercial and environmental importance. The dynamic catalysis concept will also be introduced to graduate students via an elective course developed by the principal investigator.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.