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

二氧化碳的产生是燃烧化石燃料以满足现代社会能源需求的不良后果之一。人工光合作用通过将二氧化碳重新转化为能量丰富的化学物质，创造一个受大自然启发的封闭循环，从而限制了对环境的相应影响。这一概念的技术可行性取决于催化剂的发展，这些催化剂促进二氧化碳的快速和高能效转化。研究人员最近发现了一种由富含地球的金属化合物的纳米薄片组成的催化剂的方法。这些“人造叶子”有望取代昂贵的贵金属，如铂，但由于缺乏对其工作原理的基本化学理解，这些材料的成分和详细结构的优化受到阻碍。这项研究将采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识别在电化学电池的工作环境中表现更好、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日益可持续的未来。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，以及一个关于电化学的夏季研讨会，这些研究活动与让下一代科学家接触尖端方法的广泛努力交织在一起。伊利诺伊大学芝加哥分校（University of Illinois at Chicago）在高度多元化的社区中大力招聘，以覆盖STEM中代表性不足的人群。与离子液体电解质接触的二维过渡金属二硫化物（TMDC）在将二氧化碳还原为合成气方面超过了最先进的电催化剂的性能。然而，这种卓越性能的基本基础尚未完全确定，特别是离子液体电解质和催化剂之间的协同作用。该项目将采用光谱技术的组合来建立一个支持TMDC/离子液体系统中二氧化碳减少机制的关键状态库。结合迁位实验和操作实验评价了这些状态的演化，并评价了化学排列的影响。结果增加了一个新的和未开发的一类重要的电催化反应候选者的基本知识。这项研究的主题也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热情。研究人员参加了芝加哥地区小学和高中的推广活动，从课堂上对科学教师的支持到伊利诺伊大学芝加哥分校（UIC）实验室的实地考察。他们积极指导UIC的本科生，以提高他们毕业后寻找职业道路的能力，例如，通过与本项目目标相关的研究机会，最大限度地提高学生接触尖端方法的能力。这些活动将特别关注芝加哥的西班牙裔社区成员，这一群体在STEM领域的代表性严重不足。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。

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.