CAS-Climate: Atomically Resolved Single-Molecule Microscopy of Catalytic Intermediates in CO2 Reduction

CAS-Climate：二氧化碳还原催化中间体的原子分辨单分子显微镜

• 批准号: 2203589
• 负责人: Udo Schwarz
• 金额: $ 47.39万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2203589&HistoricalAwards=false
• 关键词: CAS; Climate; Atomically; Resolved; Single

With support from the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry, a research team led by Professors Udo Schwarz and Eric Altman at Yale University is using a combination of scanning probe microscopy (SPM) methods and theory to obtain a detailed picture of the interaction between carbon monoxide (CO) and the single-molecule catalyst cobalt phthalocyanine (CoPc). The project will examine how new imaging capabilities can be used to probe the roles of surface interactions and of substituent groups on the CoPc catalysts in order to adjust the adsorption strength of CO, a key intermediate in the reduction and conversion of CO2 to methanol. This research is designed to address issues related to climate change by contributing to the creation of a reliable, carbon-neutral energy supply based on the catalytic conversion of CO2 into methanol. Methanol is a commodity chemical that can readily be stored and transported and either used as fuel directly or converted into other liquid fuels such as diesel, gasoline, or aviation kerosene. Recent work at Yale has identified immobilized CoPc molecules as a promising platform for promoting selective CO2 conversion to methanol, but little is known about how to optimize the activity, selectivity, and stability of this potential catalyst. Therefore, the research team is developing a chemical imaging approach to show how individual CoPc molecules interact with the supporting surface and with key intermediate species in the CO2 reduction process, including CO. The work has the potential to provide new methods for optimizing these interactions by tuning substituent groups on the CoPc catalyst. The detailed molecular-level understanding that emerges from this effort could lead to improvements in electrocatalytic performance. In addition to broader impacts related to the mitigation of climate change, the project will provide advanced student training opportunities in state-of-the-art imaging methods and supports outreach activities for the general public.The reduction of CO2 involves generating CO as an intermediate, therefore efficient methanol production requires that CO binding to the cobalt atom in CoPc is neither too strong nor too weak. Although CO binding can likely be fine-tuned by changing the catalyst structure, current spectroscopic methods are inadequate for understanding CO binding strength on a single-molecule basis. To alleviate this shortcoming, the research team uses advanced scanning probe microscopy methods to locally measure the CO adsorption strength as a function of catalyst structure and support, with the goal of enabling rational catalyst optimization. Key to the project are recent advances in SPM that provide the ability to image molecular structures, distinguish bond orders, and measure small distortions in molecular structures as electrons are injected into molecules using non-contact atomic force microscopy (NC-AFM) with CO-functionalized tips. For complementary information, results from NC-AFM imaging are combined with the measurement of local work function variations obtained by Kelvin probe microscopy and the electronic structure obtained through tunneling spectroscopy, which allow mapping of the positions of the highest occupied and lowest unoccupied molecular orbitals, total charge densities, and electron transfer to and from the support. As the third major element of this effort, scanning tunneling microscopy-based action spectroscopy should enable quantification on an individual molecule basis of how supports, adsorption sites and geometries, and substituent groups influence the adsorption of reactive intermediates in the conversion of CO2 to liquid fuelsThis 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.

在化学系化学测量和成像（CMI）项目的支持下，耶鲁大学的Udo施瓦茨和Eric Altman教授领导的研究小组正在使用扫描探针显微镜（SPM）方法和理论相结合的方法来获得一氧化碳（CO）和单分子催化剂酞菁钴（CoPc）之间相互作用的详细图像。该项目将研究如何使用新的成像能力来探测CoPc催化剂上的表面相互作用和取代基的作用，以调整CO的吸附强度，CO是CO2还原和转化为甲醇的关键中间体。这项研究旨在通过促进建立一个可靠的，碳中性的能源供应的基础上，二氧化碳催化转化为甲醇，以解决与气候变化有关的问题。甲醇是一种易于储存和运输的商品化学品，可直接用作燃料或转化为其他液体燃料，如柴油，汽油或航空煤油。耶鲁大学最近的工作已经确定了固定化CoPc分子作为一个有前途的平台，促进选择性CO2转化为甲醇，但鲜为人知的是如何优化这种潜在的催化剂的活性，选择性和稳定性。因此，研究小组正在开发一种化学成像方法，以显示单个CoPc分子如何与支撑表面以及CO2还原过程中的关键中间物质（包括CO）相互作用。从这一努力中产生的详细分子水平的理解可能会导致电催化性能的改善。除了与减缓气候变化有关的更广泛影响外，该项目还将提供先进的学生培训机会，使其掌握最先进的成像方法，并支持面向公众的外联活动。减少二氧化碳需要产生作为中间体的CO，因此高效的甲醇生产要求CO与CoPc中的钴原子的结合既不太强也不太弱。尽管可以通过改变催化剂结构来微调CO结合，但目前的光谱方法不足以了解单分子基础上的CO结合强度。为了缓解这一缺点，研究小组使用先进的扫描探针显微镜方法局部测量CO吸附强度作为催化剂结构和载体的函数，目标是实现合理的催化剂优化。该项目的关键是SPM的最新进展，该技术提供了成像分子结构，区分键级和测量分子结构中的小变形的能力，因为电子被注入到分子中使用非接触式原子力显微镜（NC-AFM）与CO功能化的提示。对于补充信息，从NC-AFM成像的结果相结合的局部功函数的变化，通过开尔文探针显微镜和电子结构获得通过隧道光谱，允许映射的位置的最高占用和最低未占用的分子轨道，总电荷密度，和电子转移到和从支持的测量。作为这项工作的第三个主要元素，基于扫描隧道显微镜的作用光谱学应该能够在单个分子的基础上量化载体、吸附位点和几何形状，和取代基影响二氧化碳转化为液体燃料过程中活性中间体的吸附。该奖项反映了NSF的法定使命，并通过利用基金会的智力价值进行评估，被认为值得支持和更广泛的影响审查标准。