CAREER: Engineering the Reactivity of Single Atom Electrocatalysts Beyond their Active Site

职业：设计单原子电催化剂的活性位点之外的反应性

• 批准号: 2340693
• 负责人: Joaquin Resasco
• 金额: $ 65万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-06-01 至 2029-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2340693&HistoricalAwards=false
• 关键词: CAREER; Engineering; Reactivity; Single; Atom

Electricity generation from renewable sources, such as wind and sunlight, is becoming increasingly cheap and available. To meet our nation’s decarbonization goals, however, technologies are needed that can leverage this renewable electricity to produce useful chemicals and fuels with low carbon dioxide (CO2) emissions. Electrochemical processes are poised to address this critical need. For example, the electrochemical splitting of water can produce green hydrogen, while the oxidation of green hydrogen can yield carbon free energy on demand. But the viability of these processes depends on the performance and cost of catalytic materials needed for the electrochemical reactions. These catalysts are typically composed of rare and expensive metals such as platinum, palladium, and iridium. One strategy to improve the performance of these materials is to disperse the metal as individual atoms on a high surface area support. These “single-atom” catalysts (SACs) provide maximum metal usage efficiency and display unique catalytic properties. But key fundamental questions remain about how these catalysts carry out electrocatalytic reactions and what their true structure is under operating conditions. The project seeks to develop a fundamental understanding of electrochemical catalysis over SACs, and use this understanding to design new materials with improved performance and precious metal usage efficiency. The research will be integrated with educational efforts aimed at engaging students from underrepresented groups, particularly LatinX students, and exciting them about the role of catalysis in sustainability. Currently, single-atom electrocatalysts suffer from a lack of uniformity in their active site structures. To address that issue, the project will utilize atomic layer deposition (ALD) to synthesize catalysts with highly uniform catalytic active sites deposited on precisely synthesized metal oxide nanocrystalline supports. A combination of site-specific and in situ spectroscopies will be used to understand the atomic structure of the active sites and how their structure may evolve under reaction conditions. Having identified the nature of these active sites, links will be made between their structure and catalytic behavior. These structure-property relationships will be leveraged to design catalysts with optimal activity, systematically tuning the bonding of the metal site to the oxide support. This continuous tuning will be enabled by electrochemical ion insertion into the metal oxide support. In addition to understanding how the catalytic sites respond to changes in bonding to their support, the project will further demonstrate how their properties can be controlled by changing the electrochemical medium in which they operate. The insights developed in these studies will be used to design catalysts for selective electrochemical oxidation reactions using glycerol, a major byproduct of biodiesel, as a representative substrate.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.

风能和太阳能等可再生能源发电正变得越来越便宜和容易获得。然而，为了实现我国的脱碳目标，需要利用这种可再生电力生产有用的化学品和低二氧化碳排放的燃料的技术。电化学工艺有望解决这一关键需求。例如，水的电化学分解可以产生绿色氢，而绿色氢的氧化可以按需产生无碳能源。但这些过程的可行性取决于电化学反应所需的催化材料的性能和成本。这些催化剂通常由稀有和昂贵的金属组成，如铂、钯和铱。提高这些材料性能的一种策略是将金属分散为单个原子，在高表面积的支撑上。这些“单原子”催化剂（SACs）提供了最大的金属利用效率，并显示出独特的催化性能。但是，这些催化剂如何进行电催化反应，以及它们在操作条件下的真实结构是什么，这些关键的基本问题仍然存在。该项目旨在发展对SACs电化学催化的基本理解，并利用这一理解来设计具有更高性能和贵金属使用效率的新材料。这项研究将与教育工作相结合，旨在吸引来自代表性不足群体的学生，特别是拉丁裔学生，并使他们对催化在可持续发展中的作用感到兴奋。目前，单原子电催化剂存在活性位点结构不均匀的问题。为了解决这个问题，该项目将利用原子层沉积（ALD）来合成催化剂，在精确合成的金属氧化物纳米晶体载体上沉积高度均匀的催化活性位点。位点特异性和原位光谱的结合将用于了解活性位点的原子结构以及它们的结构在反应条件下如何演变。在确定了这些活性位点的性质之后，将在它们的结构和催化行为之间建立联系。这些结构-性质关系将被用于设计具有最佳活性的催化剂，系统地调整金属位点与氧化物载体的结合。这种连续调谐将通过电化学离子插入金属氧化物支架来实现。除了了解催化位点如何对其载体的键合变化做出反应外，该项目还将进一步证明如何通过改变其工作的电化学介质来控制其性质。在这些研究中发展的见解将用于设计选择性电化学氧化反应的催化剂，使用甘油（生物柴油的主要副产物）作为代表性底物。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。