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

该提案将利用理论工具来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。由于涉及的空间尺度小、固有的复杂性和无序性以及表面原子与体积原子的高比率，纳米多孔材料不容易被实验探针探测到。这项工作将致力于理解一个鲜为人知但却引人注目的实验观察，即通过Ni- pt颗粒的电化学脱合金获得的纳米多孔铂在Ni7Pt3组成物上产生了戏剧性的最佳氧还原反应（ORR）活性，尽管在活性催化剂表面附近观察到缺乏Ni。拟议的工作将有助于发展用于运输和电力应用的改进燃料电池。它还将提供与燃料电池催化和材料特性理论模拟方法相关的教育机会。该提案将通过第一性原理理论、反应分子动力学模拟（RMD）和全局优化技术来阐明Ni-Pt和其他双金属颗粒的结构-性质关系。这一提议在范围上是雄心勃勃的，但PI是一位成熟的计算科学家，他拥有开发精致理论技术并将其成功应用于催化和材料科学中的重要问题的历史。这个提议有可能是变革性的，因为它有能力深入了解纳米级合金颗粒的特性，而这些特性很难用实验方法来评估。这项工作的新特点包括开发了一种计算方法来模拟电化学电位下的ORR，并计划从完整的纳米颗粒中提取有限大小的团簇，并对涉及ORR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了解纳米多孔多金属颗粒与电催化的关系，并利用这一理解来设计更高效、更耐用、更低成本的燃料电池，但这项工作的潜在影响将扩展到纳米颗粒在材料科学和工程领域的许多应用领域。这些因素包括能源、可持续性、环境因素和经济考虑（例如，非贵金属材料）。PI是燃料电池催化领域的领导者。作为加州理工学院材料和过程模拟中心的主任，他拥有一支强大的研究团队，负责研究燃料电池系统各组成部分之间复杂的相互作用，即催化剂、碳支撑和聚合物膜。PI将继续将其实验室开发的软件作为开源包（即LAMMPS）提供。PI也有一个良好的记录，将他的研究纳入少数民族代表性不足的群体的学习机会，并开发了一门与材料原子建模相关的课程。

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.