UNS:Nanoporous Platinum -- Atomistic Structure and Catalytic Properties Via Computational Simulations

Goddard(1512759)该提案将利用理论工具深入了解纳米多孔金属在燃料电池相关催化中的结构-功能关系。由于纳米多孔材料所涉及的空间尺度较小，其固有的复杂性和无序性，以及其高表面原子与体原子特征的比率，实验探测器不易获得这些材料。这项工作将致力于理解一个鲜为人知但值得注意的实验观察，即通过电化学去合金化获得的纳米多孔铂在Ni7Pt3组分的氧还原反应(ORR)中产生了戏剧性的最佳活性，尽管观察到活性催化剂表面附近缺乏镍。拟议的工作将有助于开发用于交通和电力应用的改进型燃料电池。它还将提供与燃料电池催化和材料性能理论模拟方法相关的教育机会。该提议将通过基于第一性原理的理论、反应分子动力学模拟(RMD)和全局优化技术来阐明镍-铂和其他双金属粒子的结构-性质关系。这项提议在范围上是雄心勃勃的，但PI是一位久负盛名的计算科学家，他有开发精细理论技术并成功地将它们应用于催化和材料科学中的重要问题的历史。这项提议具有潜在的变革性，因为它有能力在实验方法难以评估的水平上洞察纳米级合金颗粒的性质。这项工作的新特点包括开发了一种在电化学势下模拟ORR的计算方法，并计划从完整的纳米粒子中提取有限尺寸的团簇，并对ORR中涉及的吸附和反应过程的表面性质进行更深入的理论分析。虽然该提案的具体重点是理解纳米多孔多金属颗粒与电催化相关的知识，并利用这些理解来设计更高效、更耐用和更低成本的燃料电池，但这项工作的潜在影响延伸到材料科学和工程的一般领域中纳米颗粒应用的许多领域。这些因素包括能源、可持续性、环境因素和经济考虑因素(例如，非贵金属材料)。PI是燃料电池催化领域的领先者。作为加州理工大学材料和工艺模拟中心的主任，他可以接触到各级强大的研究团队，以解决燃料电池系统各种组件--即催化剂、碳载体和聚合物膜--之间的复杂相互作用。PI将继续以开源程序包(即LAMMPS)的形式提供在他的实验室开发的软件。在将他的研究纳入少数族裔代表不足群体的学习机会方面，该协会也有良好的记录，并开发了一门与材料原子建模有关的课程。

Goddard (1512759)The proposal will utilize theoretical tools to obtain insight into structure-function relationships in fuel cell related catalysis by nanoporous metals. The nanoporous materials are not readily accessible by experimental probes due to the small spatial scale involved, their inherent complexity and disorder, and their high ratio of surface- to bulk-atom characteristics. The work will be directed at understanding a poorly understood, yet remarkable, experimental observation that nanoporous platinum obtained by electrochemical dealloying of Ni-Pt particles produces a dramatic optimum activity for the oxygen reduction reaction (ORR) at the Ni7Pt3 composition despite the observed lack of Ni near the surface of the active catalyst. The proposed work will contribute to the development of improved fuel cells for transportation and power applications. It will also provide educational opportunities related to fuel cell catalysis and methods of theoretical simulation of materials properties. The proposal will elucidate the structure-property relationships in the Ni-Pt and other bimetallic particles via first-principles-based theory, reactive molecular dynamics simulations (RMD) and global optimization techniques. The proposal is ambitious in scope, but the PI is a well-established computational scientist with a history of developing refined theoretical techniques and applying them successfully to important problems in catalysis and materials science. The proposal has the potential to be transformative in regards to its ability to gain insight into the properties of nanoscale alloy particles at levels not easily assessed by experimental methods. Novel features of the work include development of a computational method for modeling ORR under electrochemical potential and a plan to extract finite-sized clusters from the complete nanoparticles and subject them to deeper theoretical analysis of the surface properties with respect to adsorption and reaction processes involved in the ORR. Although the specific focus of the proposal is on understanding nanoporous multimetallic particles as they relate to electrocatalysis and use the understanding to design more efficient, durable, and lower-cost fuel cells, the potential impact of the work extends to many areas of nanoparticle application in the general areas of materials science and engineering. These include energy, sustainability, environmental factors, and economic considerations (e.g., non-noble metal materials). The PI is a leader in fuel cell catalysis. As Director of the Materials and Process Simulation Center at Caltech, he has access to a strong team of researchers at all levels to address the complicated interplay between the various components of fuel cell systems - namely catalysts, carbon supports, and polymer membranes. The PI will continue to make software developed in his lab available as open-source packages (i.e. LAMMPS). The PI also has a good track record of incorporating his research into learning oppportunities for minority underrepresented groups and has developed a course related to atomistic modeling of materials.