Zeolite Nanosheet on Hydrogen Permeable Membrane: Coupling Catalysis with Hydrogen Removal in Non-oxidative Direct Methane Conversion

1264599由于内在的动力学和热力学限制，非氧化直接甲烷转化为更有价值和更容易运输的化学品和燃料仍然是一个巨大的挑战。美国能源情报署最近的一份报告设想，廉价而丰富的天然气作为一种原材料，可能会对世界的化学和能源供应产生重大影响。由金属/沸石(Mo/ZSM5)催化剂和氢(H2)渗透膜组成的膜反应器具有克服这些动力学和热力学障碍的潜力。膜反应器的基本特征是空间受限的含有Broensted酸中心的ZSM5通道中的Mo物种激活甲烷形成碳链，同时限制碳链长度；相对于进料平衡限制，H2渗透膜不断去除H2产物以提高转化率。本研究的主要目的是制备和描述由ZSM5片状催化剂和薄透氢陶瓷膜组成的新型管式膜反应器。研究的重点是通过ZSM5纳米片和陶瓷膜的组装来控制ZSM5的晶体尺寸，以优化甲烷(CH4)反应动力学和NDMC中的H2分离。初步数据表明，Mo/ZSM5和H2透过陶瓷膜的活性分别强烈地依赖于ZSM5的晶体尺寸和膜厚度。将使用跨学科战略来控制NDMC，并创造将反应性甲烷气体转化为高附加值燃料和化学品的新的、可能具有变革性的方法。更广泛的影响：高效的NDMC膜反应堆的开发可能导致新的热化学工艺，以满足从甲烷气体中提取高能量密度燃料的需求。该项目将沸石化学、固态碘、化学催化和分离过程的研究与教育和宣传相结合，旨在强调与能源转换相关的化学工程的重要性。教育将得到加强，将根据PI在材料、催化、分离和能源方面的研究兴趣开发一门新课程，在研究活动中从代表性较低的社区招募和指导本科生，并通过马里兰大学附近K-12学生的外联计划来加强教育。

1264599 LiuThe non-oxidative direct methane conversion (NDMC) to more valuable and easily transportable chemicals and fuels has remained a grand challenge due to the intrinsic kinetic and thermodynamic constraints. A recent report by the US Energy Information Administration envisions inexpensive and abundant natural gas as a raw material that can significantly impact the chemical and energy supplies of the world. A membrane reactor composed of a metal/zeolite (Mo/ZSM5) catalyst and a hydrogen (H2) permeable membrane has the potential to overcome these kinetic and thermodynamic barriers. The essential feature of the membrane reactor is that Mo species within spatially constrained ZSM5 channels containing Broensted acid sites activate methane to form carbon chains while concurrently restricting the carbon chain length; the H2 permeable membrane continuously removes H2 product to increase conversion relative to feed equilibrium limitations. The key objective of this research is to fabricate and describe novel tubular membrane reactors composed of ZSM5 lamellar catalysts and thin H2 permeable ceramic membranes. A focus of the research is controlling the ZSM5 crystal size by assembly of ZSM5 nanosheets and ceramic membranes to optimize methane (CH4) reaction kinetics and H2 separation in NDMC. Preliminary data show that activity of Mo/ZSM5 and H2 permeation through the ceramic membrane depends strongly on the ZSM5 crystal size and membrane thickness, respectively. A cross-disciplinary strategy will be used to control NDMC and create new and potentially transformative ways of converting reactant methane gas to high value-added fuels and chemicals. Broader Impacts: The development of efficient NDMC membrane reactors may lead to new thermochemical processes to meet the demand for high-energy density fuels from methane gas. The project integrates research on zeolite chemistry, solid state ioincs, chemical catalysis, and separation processes with an education and outreach component designed to highlight the importance of chemical engineering relevant to energy conversion. Education will be enhanced by developing a new course based upon PIs' research interests in materials, catalysis, separation, and energy, by recruiting and mentoring undergraduate students from underrepresented communities in research activities, and by outreach programs for K-12 students near the University of Maryland.