CAREER: Enhancing Atomic Mobility and Desorption Kinetics in Metal Hydrides

非技术描述：该项目旨在通过实施研究和教育推广活动，帮助发展氢经济，并激发公众对燃料电池和电动马达车载储氢主题的讨论。这些研究项目将研究限制氢作为一种实用和可行的燃料来源实施的重要的悬而未决的问题。具体地说，将使用位于美国和国外的同步加速器x射线和中子设施的最先进仪器来研究催化剂在金属氢化物中的作用。调查将围绕以下问题展开：催化剂如何促进金属氢化物粉末(如NaAlH4或LiBH4)中氢气的去除和吸收？同样的催化剂是否能增强或减少氢化物粉末中的远程原子移动？？由这笔资金发起的其他项目将包括每年与学生团队一起发起的高中设计挑战项目。这项高中计划将被称为项目能源(探索新能源-与Y世代相关的替代方案)(更新请参见project EnerG.com)。技术细节：这项提议的目标是了解催化添加剂在提高金属氢化物(特别是NaAlH4和LiBH4)中的原子迁移率和解吸率方面的影响。将研究烧结模型对一类新材料的适应性，同时结合X射线和中子散射研究，以了解这些氢化物在脱附过程中的局部晶格变化。以往了解催化剂作用的实验研究仅限于单一实验，如X射线吸收光谱、核磁共振或直接成像以了解催化剂周围的局部结构。或者，拟议的项目通过应用整个范例来处理这一问题。为了建立概念来理解过渡金属在氢化物中的作用，想法来自于一个发达的研究领域(即陶瓷烧结和致密化)，在这个领域中，人们了解了掺杂如何影响扩散和质量传输。研究将调查过渡金属催化添加剂对氢脱附过程不同阶段原子迁移率的影响。同步辐射x射线散射数据有助于理解质量传输和氢脱附在微观结构修复中的相对作用。由催化加成形成的点缺陷的浓度和类型将通过正电子湮没研究来确定。此外，原位同步加速器X射线衍射、原子对分布函数分析的中子扩散散射研究和X射线吸收光谱将使我们能够研究氢脱附和吸氢过程中的局部晶格应变、晶格非晶化和催化剂局部结构。PI有在同步加速器x射线研究中指导学生研究人员的历史吗？许多人来自代表不足的群体，通过她在历史上属于黑人的格兰布林州立大学和路易斯安那理工大学的联合教职。该项目将同时支持本科生和研究生。教育活动包括关于同步加速器x射线研究和替代能源的新课程，以及一个高中推广计划。

NON-TECHNICAL DESCRIPTION: The project is designed to aid in the development of the hydrogen economy and to stimulate public discourse on the topic of on-board vehicular hydrogen storage for fuel cells and electric motors by implementing research and educational outreach activities. The research projects will study important unanswered questions which limit the implementation of hydrogen as a practical and viable fuel source. Specifically, the role of catalysts in metal hydrides will be studied using state-of-the-art instrumentation located at synchrotron x-ray and neutron facilities within the U.S. and abroad. Investigations will surround the questions: ?How do catalysts facilitate the removal and uptake of H2 gas in metal hydride powders (e.g. NaAlH4 or LiBH4)?? and ?Do the same catalysts act to enhance or decrease long range atomic movement in the hydride powders?? Other projects instituted by this funding will include a high school design challenge project to be instituted annually with a team of students. The high school program will be called Project ENERGY (Exploring New Energy-alternatives Relevant to Generation Y) (see projectEnerG.com for updates).TECHNICAL DETAILS: The objective of this proposal is to understand the influence of catalytic additives in enhancing atomic mobility and desorption rates in metal hydrides (specifically, NaAlH4 and LiBH4). The adaptation of sintering models to a new class of materials will be investigated, while incorporating x-ray and neutron scattering studies to understand local lattice changes in these hydrides during desorption. Prior experimental investigations to understand the role of catalysts have been limited to single-experiments such as x-ray absorption spectroscopy, nuclear magnetic resonance, or direct imaging to understand the local structure around the catalysts. Alternatively, the proposed project approaches this problem by applying an entire paradigm. In order to build concepts in understanding the role of the transition metals in hydrides, ideas are taken from a well-developed field of study (i.e., ceramic sintering and densification) wherein it is understood how dopants effect diffusion and mass transport. Studies will investigate the effect of transition metal catalytic additives on atomic mobility at various stages of the H2 desorption process. Synchrotron x-ray scattering data aid in understanding the relative roles of mass transport and H2 desorption on microstructure remediation. Concentration and type of point defects formed as a result of catalytic additions will be determined using positron annihilation studies. As well, in situ synchrotron x-ray diffraction, neutron diffuse scattering studies with atomic pair distribution function analysis, and x-ray absorption spectroscopy will enable examination of local lattice strains, lattice amorphization and catalyst local structure upon hydrogen desorption and uptake. The PI has a history of mentoring student researchers at synchrotron x-ray studies ? many from underrepresented groups, through her joint faculty position between Grambling State University, a historically Black university, and Louisiana Tech University. This program will support both undergraduate and graduate students. Educational activities include new courses on synchrotron x-ray studies and alternative energy, and a high school outreach program.