COLLABORATIVE RESEARCH: Nano-Engineered MOF-Graphene Materials: New Perspectives for Reactive Adsorption and Catalysis

1133112/1133066 Bandosz/Gibbins活性炭具有高表面积（通常为1，000 - 2，000 m2 g-1），并且是强大的物理吸附剂，但是除了在高温下之外几乎没有催化活性。金属-有机骨架（MOF）材料通常是有效的催化剂，但作为吸附剂不太有效。最近，在概念验证中，我们成功地合成了GO/MOF纳米复合材料，并表明它通过表面反应和吸附的组合在从气流中去除有毒气体（氨，硫化氢）方面非常有效。纳米复合材料去除有毒气体的能力显著超过了单独的MOF或氧化石墨，并且对氨的初步结果表明，这些纳米复合材料的吸附能力可以比传统活性炭提高300%或更多。该项目将是对这种石墨烯/MOF和GO/MOF（统称为G/MOF）纳米复合材料的联合实验-理论研究，目的是确定其形成机制，原子结构，孔结构以及催化和吸附性能，实际目标是设计具有最佳吸附和催化性能的材料用于去除有毒气体。作为石墨烯基组分，将使用石墨、氧化石墨和膨胀石墨。合成后将进行表征。然后将研究NH3和H2S分别与甲烷混合与纳米复合材料的相互作用。这些系统的选择是基于吸附物的化学性质的性质和差异，在环境条件下反应吸附的需要，以及石墨烯基纳米复合材料的潜在检测能力。对于后者，可以采用电导率的变化。选择用于研究的MOF将包括具有潜在活性Cu、Cr和Fe位点的水稳定材料，例如Cu-BT或MIL-100。与实验计划并行，将使用分子模拟（Monte Carlo，混合反向Monte Carlo和分子动力学）和（从头算）密度泛函理论进行双尺度理论研究，以确定材料的原子结构，反应机制，反应吸附能力和吸附热的细节。这些理论结果将有助于指导实验计划走向有前途的材料和条件。该研究项目将提供合成条件，原子结构和孔形态之间的关系的基本理解，和分离性能的一类新的G/MOF纳米复合材料，设计用于有毒气体的去除。这些新材料可能会在其他分离和传感设备中找到应用。广泛的表面表征和应用的理论方法将导致更好地理解吸附剂和催化剂的表面化学一般。这项研究直接关系到开发新的策略，设计有效的材料，通过反应吸附在环境条件下从空气中去除有毒气体。另一个重要的技术方面是这些材料作为气体传感器的应用的可能性。如果小分子气体插入石墨层间空间内，则电导率预计会改变，并且这种现象可以用于检测低浓度范围的有毒气体。氨在GO/MOF纳米复合材料上的初步探索性研究显示，吸附能力比常规活性炭增加约三倍。因此，拟议的研究具有潜在的变革性。该项目将涉及两名研究生，两名本科生研究人员和一名来自内城科学高中的高中生。CCNY是一个少数民族服务机构，该项目将为代表性不足的群体的成员提供进行研究和获得博士学位的可能性。NCSU？AGEP/Opt-Ed和ORNL？的数学与科学研究联盟（RAMS）暑期项目也将提供机会，从代表性不足的人群中招募学生。学生的整个教育体验将基于研究与教育的整合。

1133112/1133066Bandosz/GibbinsActivated carbons possess high surface area (typically 1,000-2,000 m2g-1) and are powerful physical adsorbents, but have little catalytic activity except at high temperatures. Metal-organic framework (MOF) materials are generally effective catalysts, but are less effective as adsorbents. Recently, in a proof of concept, we have succeeded in synthesizing a GO/MOF nanocomposite material, and shown that it is very effective in removing toxic gases (ammonia, hydrogen sulfide) from gas streams through a combination of surface reaction and adsorption. The capacity of the nanocomposites to remove toxic gases significantly exceeds that of either the MOF or graphite oxide alone, and preliminary results for ammonia suggest that these nanocomposites can achieve a 300% or more increase in adsorption capacity over conventional activated carbons. This project will be a joint experimental-theoretical study of such graphene/MOF and GO/MOF (collectively, G/MOF) nanocomposites, with the aim of determining their formation mechanism, atomic structure, pore structure and catalytic and adsorption properties, with the practical goal of designing materials with optimal adsorption and catalytic properties for the removal of toxic gases. As grapheme-based components graphite, graphite oxide and exfoliated graphite will be used. Syntheses will be followed by characterization. The interactions of NH3 and H2S, separately and mixed with methane, with the nanocomposites will then be investigated. These systems are chosen based on the properties and differences in the chemical nature of the adsorbates, the need for reactive adsorption under ambient conditions, and the potential detection capabilities of graphene-based nanocomposites. For the latter the changes in electrical conductivity can be employed. MOFs chosen for the study will include water stable materials with potentially active Cu, Cr and Fe sites, such as Cu-BT or MIL-100. In parallel with the experimental program, dual scale theoretical studies using molecular simulation (Monte Carlo, Hybrid Reverse Monte Carlo and Molecular Dynamics) and (ab initio) density functional theory will be carried out to determine details of the atomic structure of the materials, the reaction mechanism, reactive adsorption capacity and heats of adsorption. These theoretical results will help direct the experimental program towards promising materials and conditions. This research project will provide fundamental understanding of the relation between synthesis conditions, atomic structure and pore morphology, and separations performance for a new class of G/MOF nanocomposites that are designed for toxic gas removal. These novel materials may find application in other separations and in sensing devices. The broad spectrum of surface characterization and theoretical methods applied will lead to a better understanding of the surface chemistry of adsorbents and catalysts in general. The research is directly relevant to developing new strategies to design effective materials for removal of toxic gases from air at ambient conditions through reactive adsorption. Another important technical aspect is the possibility of applications of these materials as gas sensors. If small molecule gases are intercalated within the graphite interlayer space the electrical conductivity is expected to change, and this phenomenon can be used to detect toxic gases at low concentration range. A preliminary exploratory study of ammonia on a GO/MOF nanocomposite showed an approximately threefold increase in adsorption capacity over conventional activated carbons. Thus, the proposed research is potentially transformative. The project will involve two graduate students, two undergraduate researchers and one high school student from an inner city science-oriented high school. CCNY is a minority serving institution, and the project would provide the possibility for a member of an under-represented group to perform research and to earn the Ph.D. NCSU?s AGEP/Opt-Ed and ORNL?s Research Alliance in Math and Science (RAMS) summer program will also provide opportunities to recruit students from under-represented populations. The whole education experience of the students will be based on the integration of research and education.