CAREER: Improving Hydrogen Storage with van der Waals Density Functional Theory

该职业奖支持与氢储存和替代能源相关的综合研究和教育计划。该研究计划解决了氢储存问题，这是氢经济的关键障碍，也是迫切需要的替代燃料。硼氢化镁（Mg(BH4)2）、氨硼烷（NH3BH3）和甲烷基材料（H2）4CH4显示出巨大的潜力，但它们只能在不切实际的高温或低温下释放或储存氢。为了解决这一问题，研究计划包括以下目标：(i)通过掺杂失稳降低Mg(BH4)2中的氢解吸温度；（ii）通过水合基取代降低NH3BH3中的解吸温度，降低活化势垒；（iii）确定比（H2）4CH4中甲烷更长的烷烃在较高温度下是否稳定。虽然这些材料性质不同，从氢的化学吸附到物理吸附，但它们都受到范德华相互作用的影响。一种新颖的密度泛函理论方法，包括完全自一致的范德华相互作用，将用于计算氢释放的温度依赖反应焓和氢解吸的障碍，使用轻推弹性带计算。在整个项目中，计算和理论工作将与实验相协调，以确定材料的特性，并显著推进氢作为替代燃料的研究。计算工具也将在项目期间得到极大的改进，因为一个关键的方法目标是将范德华密度泛函数理论与Car-Parrinello分子动力学相结合，以评估热力学稳定性。这将产生一种新的工具，用于对从水到DNA的各种材料进行建模，并通过一般公共许可提供给更大的科学界。CAREER奖还支持PI的教育和推广计划，以解决面临经济和教育挑战的高度多样化地区缺乏科学素养的问题，以及学术科学指导不足的问题。目标是(i)与当地的科学博物馆和学校合作，创建一个“能源区”，其中包括在科学咖啡馆为公众提供关于替代能源和氢燃料的展示、示范、教学模块和非正式讲座；（ii）为科学领域的研究生和博士后制定一个跨部门指导计划，以提高他们的研究技能，并向独立的职业过渡。该职业奖支持与氢储存和替代能源相关的综合研究和教育计划。作为一种无味、无色、无味和无毒的分子，氢已被确定为一种理想的燃料，可以从各种来源再生生产。它是地球上最丰富的元素，所有国家都可以获得它。它与纯氧的燃烧反应非常干净，既不会产生空气污染物，也不会产生温室气体。实际上，1公斤氢气的能量含量相当于3公斤汽油，而3公斤汽油也会产生9公斤有害的温室气体。氢虽然是理想的燃料，但没有得到广泛应用的原因是氢的生产、储存和使用等方面存在问题。这个研究项目将解决储氢问题。该项目的主要目标是研究和操纵几种材料的性质，如硼氢化镁、氨硼烷和被称为h4烷烃的甲烷基材料，这些材料显示出巨大的储氢潜力。该项目的重点将是利用新的理论和计算方法在环境压力和温度下稳定这些材料。这些计算工作将与实验研究相协调，以确定材料的特性，并显著推进氢作为替代燃料的研究。该项目还将产生一种新的计算工具，用于对各种材料进行建模，这些材料显示出一种特殊的粘合，这使得最先进的计算技术的直接应用具有挑战性。由此产生的计算工具将通过一般公共许可提供给更大的科学界。CAREER奖还支持PI的教育和推广计划，以解决面临经济和教育挑战的高度多样化地区缺乏科学素养的问题，以及学术科学指导不足的问题。目标是(i)与当地的科学博物馆和学校合作，创建一个“能源区”，其中包括在科学咖啡馆为公众提供关于替代能源和氢燃料的展示、示范、教学模块和非正式讲座；（ii）为科学领域的研究生和博士后制定一个跨部门指导计划，以提高他们的研究技能，并向独立的职业过渡。

TECHNICAL SUMMARYThis CAREER award supports an integrated research and education plan related to hydrogen storage and alternative energy. The research plan addresses the hydrogen-storage problem, a critical barrier to a hydrogen economy and an urgently needed alternative fuel. Magnesium borohydride Mg(BH4)2, ammonia borane NH3BH3, and methane-based material (H2)4CH4 show great potential, but they release or store hydrogen only at impractical high or low temperatures. To resolve this problem, the research plan includes the following objectives: (i) lowering the hydrogen desorption temperature in Mg(BH4)2 by destabilization through doping; (ii) lowering the desorption temperature in NH3BH3 by substitutions in the hydridic group to lower the activation barrier; and (iii) determining whether alkanes longer than the methane in (H2)4CH4 can be stable at higher temperatures. While these materials are different in nature, reaching from chemisorption to physisorption of hydrogen, they are all influenced by van der Waals interactions.A novel density functional theory approach that includes van der Waals interactions fully self-consistently will be used to calculate temperature-dependent reaction enthalpies for the hydrogen release and barriers to hydrogen desorption using nudged elastic band calculations. Throughout the project, computational and theoretical efforts will be coordinated with experiments to determine materials' properties and significantly advance research on hydrogen as an alternative fuel. Computational tools will also be greatly improved during the project, since a key methodological goal is to combine van der Waals density functional theory with Car-Parrinello molecular dynamics to evaluate thermodynamic stabilities. This will result in a new tool for modeling a wide range of materials from water to DNA and be made available to the larger scientific community through a general public license.This CAREER award also supports the PI's educational and outreach plans of addressing the lack of scientific literacy in a highly diverse region facing economic and educational challenges, and inadequate mentoring in academic science. The objectives are (i) to work with the local science museum and schools to create an "Energy Zone" that will include a display, demonstration, teaching module, and informal talks at the Science Café for the general public about alternative energy and hydrogen as fuel; and (ii) to develop an interdepartmental mentoring program for graduate students and postdocs in the sciences to improve their research skills and transition to independent careers.NONTECHNICAL SUMMARYThis CAREER award supports an integrated research and education plan related to hydrogen storage and alternative energy. As a tasteless, colorless, odorless, and nontoxic molecule, hydrogen has been identified as an ideal fuel that can be produced renewably from a variety of sources. It is the most abundant element on Earth, and all nations have access to it. Its combustion reaction with pure oxygen is perfectly clean, creating neither air pollutants nor greenhouse gases. In practical terms, the energy content of 1 kg of hydrogen corresponds to 3 kg of gasoline, whereas 3 kg of gasoline also produce 9 kg of undesirable greenhouse gas. Although hydrogen is the ideal fuel, the reason why it is not widely used is that there are problems related to hydrogen production, storage, and use. This research program will address the hydrogen-storage problem. The primary goal of the project is to investigate and manipulate properties of several materials, such as magnesium borohydride, ammonia borane, and methane-based materials known as H4-alkanes which show great potential for hydrogen storage. The focus of the project will be to stabilize such materials at ambient pressures and temperatures by utilizing novel theoretical and computational methods. These computational efforts will be coordinated with experimental studies to determine the materials' properties and significantly advance research on hydrogen as an alternative fuel. The project will also result in a new computational tool for modeling a wide range of materials which display a particular kind of bonding that makes straightforward applications of state-of-the-art computational techniques challenging. The resulting computational tool will be made available to the larger scientific community through a general public license.This CAREER award also supports the PI's educational and outreach plans of addressing the lack of scientific literacy in a highly diverse region facing economic and educational challenges, and inadequate mentoring in academic science. The objectives are (i) to work with the local science museum and schools to create an "Energy Zone" that will include a display, demonstration, teaching module, and informal talks at the Science Café for the general public about alternative energy and hydrogen as fuel; and (ii) to develop an interdepartmental mentoring program for graduate students and postdocs in the sciences to improve their research skills and transition to independent careers.