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”分子或催化剂来快速有效地进行。当需要能量时，氢和氧可以在一个被称为燃料电池的设备中重新组合，以产生所需的电力。不幸的是，目前将水转化为氧气（氧气进化反应，OER）和氧气再转化为水（氧气还原反应，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。在这个奖项中，鲍灵格林州立大学的Ksenjia Glusac博士正在研究不仅加速OER和ORR，而且便宜无毒的催化剂。她的模型催化剂是由碳和氮等地球上丰富的元素制成的，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一种基本材料。该项目还包括旨在将能源相关主题引入K-12、大学和普通公共教育的推广活动。提高公众的能源知识是实现对与能源有关的行为和政策作出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-空气电池中的关键反应过程。石墨烯的高导电性，加上氮位点的催化性能，使n掺杂石墨材料成为无金属OER/ORR催化的优秀候选者。然而，对n掺杂材料催化机理的理解是有限的，这阻碍了性能改善的新一代材料的发展。在这个项目中，鲍灵格林州立大学的Ksenjia Glusac博士得到了化学催化项目的支持，研究n掺杂碳材料的分子模型催化剂，目标是确定导致高效OER和ORR催化的理想结构基元。特别强调的是导致可逆（双功能）OER/ORR催化的结构，因为电催化的可逆性与催化反应过电位的降低直接相关，从而提高催化效率。Glusac博士的研究成果使她能够通过n掺杂结构获得电催化OER/ORR的机理见解，并开发了一种化学方法，用于将有效的分子基元植入石墨材料中。此外，Glusac实验室的活动还产生了更广泛的社会影响，这些活动专注于在K-12、大学和公共教育中实施与能源相关的主题。提高公众的能源知识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.