Catalytic Activation, Spillover, and Storage of Hydrogen on Transition-metal/MOFs

过渡金属/MOF 上氢的催化活化、溢出和储存

• 批准号: 0929207
• 负责人: Yun Hu
• 金额: $ 30.27万
• 依托单位: Michigan Technological University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0929207&HistoricalAwards=false
• 关键词: Catalytic; Activation; Spillover; Storage; Hydrogen

0929207 Hu This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Metal-organic frameworks (MOFs) are potential candidates for H2 storage because they can reversibly absorb hydrogen at low temperatures. The critical issue is their low hydrogen capacity at room temperature or above, because the interaction between molecular hydrogen and MOFs is weak. Very recently, however, it was found that hydrogen capacities of MOFs can be increased by almost 10 times via atomic hydrogen adsorption. Currently, introduction of atomic hydrogen into MOFs is based on a catalytic method via a secondary spillover approach: hydrogen molecules are first dissociate into atoms on Pt metal catalyst, followed by the primary spillover of atomic hydrogen onto the surface of an activated carbon support. Then, the hydrogen atoms present on activated carbon migrate via a secondary spillover to the MOF surface. It was demonstrated that the hydrogen adsorption and desorption kinetics are strongly dependent on the carbon bridge between the Pt and the MOF, which controls the atomic hydrogen migration between them. The goal of this project is to accelerate the hydrogen adsorption and desorption by directly supporting metal catalysts on MOFs without carbon bridges. The specific hypothesis is that the migration of hydrogen atoms generated on catalyst directly to the MOF via a primary spillover should be much faster than that of atomic hydrogen from the catalyst to the MOF with carbon bridges. We based the hypothesis on the observations that 1) hydrogen adsorption and dissociation on Pt catalyst are fast, whereas the spillover of hydrogen from Pt metal to its support is a slow process, 2) when hydrogen concentration on surface increases, its spillover decreases, and 3) the migration of atomic hydrogen is faster on MOFs than on carbon materials. Based on these observations, the experimental focus of this proposal is on the bondings and spillover of atomic hydrogen on TM/MOF materials (TM=Pt, Pd, Rh, Ru, or Ni). The specific aims are to: (1) to examine the effects of spillover-steps on kinetics of hydrogen adsorption and desorption of MOFs; (2) to evaluate the bondings and migration of atomic hydrogen on MOFs; (3) to examine the effect of atomic hydrogen adsorption on crystal structures of MOFs; and (4) to evaluate new TM/MOF materials for hydrogen adsorption and desorption as well as cyclability. This research has significant intellectual merit. The interaction between the atomic hydrogen and MOFs has not been studied experimentally, even almost not theoretically. Such an interaction will be subjected to a comprehensive assessment in this project, which can provide useful information for designing MOF-based hydrogen storage materials, separation membranes, adsorbents, and hydrogenation catalysts. Knowledge about the spillover of adsorbed species at high pressure is not available, because current information regarding the spillover on catalysts was obtained from low-pressure experiments. The evaluation of hydrogen spillover at high pressure by using in-situ FTIR in this project will provide useful information to understand heterogeneous catalytic mechanisms of important industrial processes, most of which are based on high pressure catalytic reactions.This project can have a broad impact. The highly effective storage materials, which will be developed here, can lead to the decrease of hydrogen storage cost and will impact commercial feasibility of fuel cell vehicles, thus reducing requirement of oil. The knowledge about atomic hydrogen spillover and adsorption can impact development of catalysts for chemical industries. This project has also strong impacts on the education of students. A special program "Summer Institute in Hydrogen Energy" will be created. It will promote the technology of hydrogen energy into high school science classrooms via training high school teachers. This would increase female students in science and engineering schools of colleges, because high school teachers have a tremendous impact on their students' future interests and pursuits. Furthermore, two graduate and one undergraduate students will work as important part of a diverse team, and they will gain hands-on experience designing, building, and running complex experiments. In addition, this project can increase their abilities to accept high school students as summer interns for renewable energy studies.

0929207 Hu 该奖项是根据 2009 年美国复苏和再投资法案（公法 111-5）资助的。金属有机框架（MOF）是氢气存储的潜在候选者，因为它们可以在低温下可逆地吸收氢气。关键问题是它们在室温或更高温度下的氢容量较低，因为分子氢和 MOF 之间的相互作用很弱。然而，最近发现，通过原子氢吸附，MOF 的氢容量可以增加近 10 倍。目前，将原子氢引入MOF是基于二次溢出方法的催化方法：氢分子首先在Pt金属催化剂上解离成原子，然后原子氢首次溢出到活性炭载体的表面上。然后，活性炭上存在的氢原子通过二次溢出迁移到 MOF 表面。结果表明，氢吸附和解吸动力学强烈依赖于 Pt 和 MOF 之间的碳桥，碳桥控制着它们之间的原子氢迁移。该项目的目标是通过在没有碳桥的MOFs上直接负载金属催化剂来加速氢的吸附和解吸。具体假设是，催化剂上产生的氢原子通过一次溢出直接迁移到 MOF 的速度应该比原子氢从催化剂到具有碳桥的 MOF 的迁移速度快得多。我们的假设基于以下观察结果：1）Pt 催化剂上的氢吸附和解离速度很快，而氢从 Pt 金属到其载体的溢出是一个缓慢的过程，2）当表面氢浓度增加时，其溢出减少，3）原子氢在 MOF 上的迁移比在碳材料上更快。基于这些观察，本提案的实验重点是原子氢在TM/MOF材料（TM=Pt、Pd、Rh、Ru或Ni）上的键合和溢出。具体目的是：（1）研究溢出步骤对MOFs氢吸附和解吸动力学的影响； (2) 评估原子氢在MOFs上的成键和迁移； (3)考察原子氢吸附对MOFs晶体结构的影响； (4)评估新型TM/MOF材料的氢吸附、解吸以及循环性能。这项研究具有重要的智力价值。原子氢与 MOF 之间的相互作用尚未经过实验研究，甚至几乎没有在理论上进行过研究。本项目将对这种相互作用进行全面评估，为设计基于MOF的储氢材料、分离膜、吸附剂和加氢催化剂提供有用的信息。由于目前有关催化剂溢出的信息是从低压实验中获得的，因此无法获得有关高压下吸附物质溢出的知识。该项目中使用原位 FTIR 评估高压氢气溢出将为了解重要工业过程的非均相催化机制提供有用的信息，其中大多数工业过程都是基于高压催化反应。该项目可以产生广泛的影响。这里将开发的高效存储材料可以降低储氢成本，并将影响燃料电池汽车的商业可行性，从而减少对石油的需求。关于原子氢溢出和吸附的知识可以影响化学工业催化剂的发展。该项目对学生的教育也产生了重大影响。将创建一个特别项目“氢能夏季学院”。通过培训高中教师，将氢能源技术推广到高中科学课堂。这将增加大学理工学院的女学生数量，因为高中教师对学生未来的兴趣和追求有着巨大的影响。此外，两名研究生和一名本科生将作为多元化团队的重要组成部分，他们将获得设计、构建和运行复杂实验的实践经验。此外，该项目还可以提高他们接受高中生作为可再生能源研究暑期实习生的能力。