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Electrocatalytic Studies at Single, Structurally Well-defined Nanoparticles

单一、结构明确的纳米粒子的电催化研究

基本信息

批准号：
1855980
负责人：
Richard Crooks
金额：
$ 49.5万
依托单位：
University of Texas at Austin
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-01 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1855980&HistoricalAwards=false
关键词：
Electrocatalytic Studies Single Structurally Well

项目摘要

Professors Richard M. Crooks and Graeme Henkelman of the University of Texas at Austin are supported by the Chemical Catalysis Program of the Division of Chemistry to undertake fundamental studies of catalytic materials. The project is aimed at developing a better understanding of nanometer-scale electrocatalysts. The historical approach for developing new catalysts is based on the Edisonian method of using scientific intuition followed by trial-and error-testing. With the advent of very powerful computers, however, it has become possible to imagine designing catalysts using sophisticated calculations. Accordingly, the main scientific goal of the present research project is to experimentally test the validity of this approach to catalyst design. To accomplish this goal, individual, well-defined nanoparticles are first synthesized, structurally characterized and their electrocatalytic properties evaluated. This initiates an experimental-theoretical iterative relationship intended to refine theoretical tools to the point that they will eventually be sufficiently sophisticated to be used to design more effective electrocatalysts from first principles. Electrocatalysts are important for converting chemical fuels, like hydrogen, into energy, and also for the opposite family of reactions in which energy is converted to and stored in the form of fuels. With rising concerns over the security and sustainability of the nation's energy future, and the scarcity of several key catalytic materials, it is more important than ever to efficiently design more accessible and effective electrocatalysts. During the course of conducting this research, students are provided with the technical knowledge necessary to contribute toward a clean-energy future and the communication skills necessary to convey the importance of energy-related science to citizens and the nation's political leadership. The central objective of this project is to synthesize, characterize, and evaluate the electrocatalytic performance of individual nanoparticles (NPs), and then correlate their properties to those calculated using first-principles theory. To address this objective, three specific aims are identified. Specific aim 1 commences with the discovery of methods for controlling the electrosynthesis of single platinum NPs (PtNPs) onto the tips of individual, nanometer-scale carbon electrodes. Detailed surface structural characterization of these materials is determined using electron microscopy, nanobeam diffraction, and scanning tunneling microscopy. This structural information is used to predict, using first-principles theory, the electrocatalytic efficiency of these materials for carbon monoxide (CO) and formic acid oxidation. CO oxidation is selected for study because it is one of the simplest electrochemical reactions reported in literature in which clear effects of NP structure on electrocatalytic activities have been observed. It also often forms as an intermediate or by-product in electrocatalytic oxidation reactions of organic fuels. The theoretical approach involves defining particular descriptors for these reactions. Initially, these descriptors will be determined by postulating reaction mechanisms and then calculating binding energies of reaction intermediates. The resulting theoretical predictions are then experimentally tested. Specific aim 2 advances the foregoing methodology by expanding the library of achievable surface structures, which in turn provides a more rigorous test of theory. Finally, in specific aim 3, the scope of the project expands further to include other single-NP systems, including gold NPs and single-atom alloyed NPs. In this part of the project, theory guides the choice of electrocatalytic reactions and the combinations of materials tested. The goal of this aim is to demonstrate the scope of the methodology and to further challenge the predictive reliability of theory.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.

Richard M.得克萨斯大学奥斯汀分校的克鲁克斯和格雷姆·亨克尔曼得到了化学系化学催化项目的支持，从事催化材料的基础研究。该项目旨在更好地了解纳米尺度的电催化剂。开发新催化剂的历史方法是基于爱迪生的方法，即使用科学直觉，然后进行试验和错误测试。然而，随着功能非常强大的计算机的出现，使用复杂的计算来设计催化剂已经成为可能。因此，本研究项目的主要科学目标是通过实验测试这种催化剂设计方法的有效性。为了实现这一目标，首先合成单个的、定义明确的纳米颗粒，对其结构进行表征，并对其电催化性能进行评估。这启动了一个实验-理论迭代关系，旨在完善理论工具，使其最终足够复杂，可用于从第一原理设计更有效的电催化剂。电催化剂对于将化学燃料（如氢气）转化为能量以及将能量转化为燃料并以燃料形式储存的相反反应家族都很重要。随着人们对国家能源未来的安全性和可持续性的日益关注，以及几种关键催化材料的稀缺，有效设计更容易获得和有效的电催化剂比以往任何时候都更加重要。在进行这项研究的过程中，学生提供必要的技术知识，以促进清洁能源的未来和必要的沟通技巧，传达能源相关科学的重要性，以公民和国家的政治领导。该项目的中心目标是合成，表征和评估单个纳米颗粒（NPs）的电催化性能，然后将其特性与使用第一性原理理论计算的特性相关联。为实现这一目标，确定了三个具体目标。具体目标1开始于发现用于控制将单个铂NP（PtNP）电合成到单个纳米级碳电极的尖端上的方法。使用电子显微镜，纳米束衍射和扫描隧道显微镜确定这些材料的详细表面结构表征。这种结构信息是用来预测，使用第一原理理论，这些材料的一氧化碳（CO）和甲酸氧化的电催化效率。选择CO氧化进行研究是因为它是文献中报道的最简单的电化学反应之一，其中观察到NP结构对电催化活性的明显影响。它还经常作为有机燃料的电催化氧化反应中的中间产物或副产物形成。理论方法包括为这些反应定义特定的描述符。最初，这些描述符将通过假定反应机理，然后计算反应中间体的结合能来确定。由此产生的理论预测，然后实验测试。具体目标2通过扩展可实现的表面结构库来推进前述方法，这反过来又提供了更严格的理论测试。最后，在具体目标3中，该项目的范围进一步扩大，以包括其他单纳米粒子系统，包括金纳米粒子和单原子合金纳米粒子。在项目的这一部分，理论指导电催化反应的选择和测试材料的组合。该奖项反映了NSF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。