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

太阳以阳光的形式向我们的星球提供大量的能量。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，需要开发将太阳能“装瓶”成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氢和氧分子。 这种水分解过程需要“辅助”分子或催化剂，以快速有效地发生。当需要能量时，氢气和氧气可以在一种称为燃料电池的装置中重新组合，以按需发电。不幸的是，目前将水转化为氧气（氧气释放反应或OER）和氧气再转化为水（氧气还原反应或ORR）的化学反应太慢且效率低下，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。在这个奖项中，绿色州立大学的Ksenjia Glusac博士正在研究不仅能加速OER和ORR，而且价格低廉、无毒的催化剂。她的模型催化剂由地球上丰富的元素制成，如碳和氮，并利用石墨烯的高导电性，石墨烯是铅笔中发现的石墨的基石材料。该项目还包括旨在将能源相关主题引入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实现能源相关行为和政策的知情决策的必要步骤。析氧反应（OER）和氧还原反应（ORR）是太阳能水分解装置、燃料电池和金属-空气电池中发生的关键过程。石墨烯的高导电性与氮位点的催化性能相结合，使得N掺杂的石墨烯材料成为无金属OER/ORR催化的优异候选者。然而，N掺杂材料的催化机理理解是有限的，抑制了具有改进性能的新一代材料的开发。在该项目中，Bowling绿色州立大学的Ksenjia Glusac博士得到化学催化计划的支持，研究N掺杂碳材料的分子模型催化剂，目标是精确定位导致有效OER和ORR催化的理想结构基序。特别强调的是放在结构上，导致可逆的（双功能）OER/ORR催化，因为电催化可逆性是直接关联到催化反应的过电位的降低，导致更大的催化效率。Glusac博士的研究结果使她能够通过N掺杂结构获得电催化OER/ORR的机理见解，并开发出一种将有效分子基序应用于石墨烯材料的化学方法。此外，Glusac实验室的活动产生了更广泛的社会影响，这些活动侧重于将能源相关主题纳入K-12，大学和公共教育。提高公众的能源知识水平是使公众能够就与能源有关的行为和政策作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.