Chemical and electronic states in chalcogenide-based electrocatalytic systems during CO2 reduction

二氧化碳的产生是化石燃料燃烧以满足现代社会能源需求的不良结果之一。人工光合作用提供了一种方法，通过将二氧化碳重新转化为能量丰富的化学物质，创造一个受自然启发的封闭循环，从而限制对环境的相应影响。这一概念的技术可行性取决于能够促进二氧化碳快速转化和高能源效率的催化剂的开发。研究人员最近发现了一种方法，可以制造由纳米级的地球薄片组成的催化剂，其中含有丰富的金属化合物。这些“人造叶子”显示出取代铂等昂贵贵金属的前景，但由于缺乏对它们工作的化学原理的基本了解，这些材料的成分和详细结构的优化受到阻碍。这项研究将利用各种实验和分析工具来更好地理解这些原理，并利用所获得的知识来确定在电化学电池的工作环境中性能更好、更稳定的催化剂。这项工作有助于推动社会走向一个基于封闭碳循环的越来越可持续的未来。研究活动与让未来几代科学家接触尖端方法的广泛努力交织在一起，通过本科生和高中生的研究实习，从K-12学校到大学设施的实地考察，以及关于电化学的夏季研讨会。伊利诺伊大学芝加哥分校高度多样化的社区正在积极招募人员，以接触在STEM中代表性不足的人群。在将二氧化碳还原为合成气方面，与离子液体电解质接触的二维过渡金属二卤化物(TMDC)的性能超过了最先进的电催化剂的性能。然而，这种优异性能的根本基础尚未完全确定，特别是离子液体电解液和催化剂之间的协同作用。该项目将使用光谱技术的组合来建立一个临界状态库，以支持TMDC/离子液体系统中二氧化碳还原的机制。通过非原位实验和操作数实验相结合的方法评估了状态的演化，并对化学排列的影响进行了评估。这些结果增加了一类新的、未被探索的重要电催化反应候选者的基础知识。这项研究的主题还推动了一项教育计划，在未来几代科学家和技术人员中培养对科学事业的兴奋。研究人员参与了芝加哥地区小学和高中的外展活动，范围从课堂上的科学教师支持到伊利诺伊大学芝加哥分校(UIC)的实验室实地考察。他们积极指导UIC的本科生，提高他们在毕业后找到职业道路的能力，例如，通过与本项目目标相关的研究机会，最大限度地增加学生接触尖端方法的机会。这些活动将特别关注芝加哥拉美裔社区的成员，他们在STEM领域的代表性严重不足。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。

The generation of carbon dioxide is one undesirable outcome of the combustion of fossil fuels to fulfill the energy needs of modern society. Artificial photosynthesis offers means to limit the corresponding impact in the environment by reconverting the carbon dioxide to energy-rich chemicals, creating a closed cycle that is inspired by nature. The technological viability of this concept hinges on the development of catalysts that promote the conversion of carbon dioxide at fast rates and high energy efficiency. The investigators have recently discovered a way to make catalysts consisting of nanosized flakes of earth abundant metal compounds. These "artificial leaves" have shown promise as replacements for expensive noble metals such as platinum, but optimization of the composition and detailed structure of these materials is hampered by a lack of fundamental understanding of the chemical principles by which they work. The research will employ a variety of experiments and analysis tools to better understand those principles and use the knowledge gained to identify catalysts that perform better and are more stable in the working environment of an electrochemical cell. The work contributes to moving society toward an increasingly sustainable future based on a closed carbon cycle. The research activities are intertwined with broad efforts to expose future generations of scientists to cutting-edge methodologies, through research internships for undergraduate and high school students, field trips from K-12 schools to university facilities, and a summer workshop on electrochemistry. Recruitment is vigorous among the highly diverse community at the University of Illinois at Chicago, to reach populations underrepresented in STEM.Two-dimensional transition metal dichalcogenides (TMDC) in contact with ionic liquid electrolytes exceed the performance of state-of-the-art electrocatalysts toward the reduction of carbon dioxide to synthesis gas. However, the fundamental underpinnings of this outstanding performance have not yet been fully ascertained, especially synergies between the ionic liquid electrolyte and the catalyst. The project will employ a combination of spectroscopic techniques to build a library of critical states that underpin the mechanisms of carbon dioxide reduction in TMDC/ionic liquid systems. The evolution of the states is assessed by combining ex situ and operando experiments, and the effect of chemical permutations is evaluated. The outcomes increase the fundamental knowledge of a new and unexplored class of candidates for an important electrocatalytic reaction. The topics of this research also drive an educational plan that fosters excitement about the scientific enterprise in future generations of scientists and technologists. The researchers participate in outreach events at Chicago-area elementary and high schools, spanning from the support of science teachers in the classroom to field trips to laboratories at the University of Illinois at Chicago (UIC). They actively mentor undergraduate students at UIC to enhance their ability to find career paths after graduation, for instance, through research opportunities relevant to the goals of this project, maximizing the exposure of the student to cutting-edge methodologies. These activities will have a special focus on members of Chicago's Hispanic communities, a large population that is severely underrepresented in STEM fields.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.