SusChEM: Metal-Free Catalysts for Oxygen Evolution and Oxygen Reduction Reactions: From Molecular Models to Graphene-Based Electrocatalysts

太阳以阳光的形式为我们的星球提供了大量的能量。这种太阳能的一小部分就足以满足我们的能源需求。然而，为了有效地利用太阳能，需要开发出将来自太阳的能量“瓶装”成一种化学形式的太阳能燃料的方法。制造太阳能燃料的一种方法是将水分解成气态的氢分子和氧分子。这个分解水的过程需要“辅助”分子或催化剂，才能快速而有效地发生。当需要能源时，氢和氧可以在一种被称为燃料电池的装置中重新组合，按需发电。不幸的是，目前将水转化为氧气(放氧反应，简称OER)并将氧气转化为水(氧气还原反应，简称ORR)的化学反应速度太慢，效率太低，无法成为化石燃料的竞争性替代品。化学家们还没有发现可以加速这些过程的实用催化剂。在这一奖项中，鲍林格林州立大学的Ksenjia Glusac博士正在研究不仅可以加速OER和ORR，而且廉价和无毒的催化剂。她的模型催化剂是由碳和氮等富含稀土的元素制成的，并利用了石墨烯的高导电性，石墨烯是铅笔中发现的石墨的积木材料。该项目还包括旨在将与能源有关的主题引入K-12、大学和普通公众教育的外联活动。提高公众的能源素养是对能源相关行为和政策做出明智决策的必要步骤。放氧反应(OER)和氧气还原反应(ORR)是发生在太阳能分水装置、燃料电池和金属-空气电池中的关键过程。石墨烯的高导电性，再加上氮位的催化性能，使氮掺杂的石墨烯材料成为无金属OER/ORR催化的极佳候选者。然而，人们对氮掺杂材料催化机理的了解有限，阻碍了性能更好的新一代材料的发展。在这个项目中，鲍林格林州立大学的Ksenjia Glusac博士受到化学催化计划的支持，研究氮掺杂碳材料的分子模型催化剂，目标是精确定位导致高效OER和ORR催化的理想结构基序。特别强调导致可逆(双功能)OER/ORR催化的结构，因为电催化的可逆性与催化反应的过电位的降低直接相关，从而产生更高的催化效率。Glusac博士的研究结果使她能够从机理上深入了解N掺杂结构对OER/ORR的电催化作用，并开发出一种将有效的分子基序落实到石墨化材料中的化学方法。此外，格卢萨克实验室的活动产生了更广泛的社会影响，这些活动的重点是将与能源有关的主题落实到K-12、大学和公共教育中。提高公众的能源素养是让公众能够对与能源有关的行为和政策做出知情决策的必要步骤。

The sun delivers a large amount of energy to our planet in the form of sunlight. A very small fraction of this solar energy is sufficient to satisfy our energy demands. However, to use the sun's energy efficiently, ways to "bottle" the energy from the sun into a chemical form of solar fuel need to be developed. One approach to creating solar fuels is to split water into gaseous hydrogen and oxygen molecules. This water splitting process needs "helper" molecules, or catalysts, to occur rapidly and efficiently. When energy is needed, the hydrogen and oxygen can then be recombined in a device known as a fuel cell to produce electricity on demand. Unfortunately, the current chemical reactions that converts water into oxygen (the oxygen-evolving reaction, or OER) and oxygen back into water (the oxygen reduction reaction, or ORR) are too slow and inefficient to be a competitive replacement for fossil fuels. Chemists have yet to discover practical catalysts that can accelerate these processes. In this award, Dr. Ksenjia Glusac of Bowling Green State University is investigating catalysts that not only accelerate OER and ORR, but also are inexpensive and non-toxic. Her model catalysts are made of earth-abundant elements, such as carbon and nitrogen, and utilize the high conductivity of graphene, a building block material of graphite found in pencils. The project also includes outreach activities that aim at introducing energy-related topics into K-12, college and general public education. Raising public energy literacy is a necessary step towards allowing informed decision-making on energy-related behaviors and policies.The oxygen evolving reaction (OER) and the oxygen reduction reaction (ORR) are key processes occurring in solar water splitting devices, fuel cells and metal-air batteries. The high conductivity of graphene, coupled with the catalytic performance of nitrogen sites makes N-doped graphenic materials excellent candidates for metal-free OER/ORR catalysis. However, the mechanistic understanding of catalysis by N-doped materials is limited, inhibiting the development of a new generation of materials with improved performance. In this project, Dr. Ksenjia Glusac of Bowling Green State University is supported by the Chemical Catalysis Program to investigate molecular model catalysts of N-doped carbon materials, with the goal of pinpointing the ideal structural motifs that lead to efficient OER and ORR catalysis. Particular emphasis is placed on structures that lead to reversible (bifunctional) OER/ORR catalysis because the electrocatalytic reversibility is directly linked to the decrease in the overpotential of the catalyzed reaction, resulting in greater catalytic efficiency. Dr. Glusac's research results allow her to obtain mechanistic insights into electrocatalytic OER/ORR by N-doped structures and develop a chemical methodology for implementing effective molecular motifs into graphenic materials. Furthermore, broader societal impacts result from activities in the Glusac laboratory that focus on implementing energy-related topics into K-12, college and public education. Raising public energy literacy is a necessary step towards allowing informed decision-making on energy-related behaviors and policies by the general public.