Collaborative Research: First-Principles Engineering of Nanoscale Kinetics in Advanced Hydrides

氢作为汽车燃料的普遍采用，关键不仅取决于以高体积和重量密度在车上储存氢的能力，还取决于以足够快的速度提取氢的能力。最近的实验和理论研究已经确定了几种新的复杂氢化物，它们的热力学性质和材料储存能力接近实际水平。然而，所有这些材料的动力学都非常差。智力优势：所提出的工作的重点是开发一种系统的、合理的方法来设计具有快速（脱）氢化动力学和有利热力学的新型纳米结构材料，使用最先进的科学计算。第一性原理建模的准确预测能力将用于预测和理解涉及氢释放和吸收的微观动力学过程，并设计具有改进性能的新材料/催化剂系统。对化学反应、扩散途径和控制氢摄取和释放动力学的相变进行深入的原子性研究。研究了控制氢-金属结合强度的基本因素、表面结构和有限尺寸对氢化物纳米颗粒热力学和动力学的影响。掺杂剂和纳米级催化剂在实现快速动力学和可逆性方面的作用将在原子水平上得到阐明。更广泛的影响：建议的工作将有助于计算材料科学课程的发展。此外，西北大学和加州大学洛杉矶分校之间将有学生交换，因为每个小组的学生都有机会广泛访问对方。研究结果将通过研究生教育和向本科生介绍计算方法来传播。预期学生所获得的技能，例如在使用计算模型和模拟方面的技能，将为他们将来在工业和教育界的工作做好准备。最后，该研究项目的成功完成将极大地帮助开发用于清洁、环保乘用车的新型储氢系统。

General adoption of hydrogen as a vehicular fuel depends critically not only on the ability to store hydrogen on-board at high volumetric and gravimetric densities, but also on the ability to extract it at sufficiently rapid rates. Recent experimental and theoretical studies have identified several new complex hydrides with thermodynamic properties and material storage capacities approaching practical levels. However, all these materials suffer from extremely poor kinetics. Intellectual merit: The focus of the proposed work is to develop a systematic, rational approach to designing novel nanostructured materials with fast (de)hydrogenation kinetics and favorable thermodynamics using state-of-the-art scientific computing. The accurate predictive power of first-principles modeling will be used to forecast and understand the microscopic kinetic processes involved in the hydrogen release and uptake and to design new material/catalyst systems with improved properties. An in-depth atomistic picture of the chemical reactions, diffusion pathways, and phase changes controlling the kinetics of hydrogen uptake and release will be developed. Fundamental factors that control hydrogen-metal bond strength, the role of surface structure and finite size on the thermodynamics and kinetics of hydride nanoparticles will also be investigated. The effect of dopants and nanoscale catalysts in achieving fast kinetics and reversibility will be elucidated at the atomic level. Broader impact: The proposed work will aid in the development of computational materials science courses. In addition, there will be student exchange between Northwestern and UCLA, as students from each group will have the opportunity for extensive visits to the other. The results of the research will be disseminated through the education of graduate students, and introduction of undergraduate students to computational methods. It is expected that the skills acquired by the students, for example in the use of computational modeling and simulation, will prepare them for future work in the industrial and educational communities. Finally, successful completion of this research program will greatly assist the development of new hydrogen storage systems for clean, environmentally safe passenger vehicles.