Structure-Function Relationships for Early Transition Metal Carbide and Nitride Cataysts

早期过渡金属（IV-VI族）碳化物和氮化物是一类令人着迷的材料，具有广泛的潜在应用，包括用作能源和环境可持续过程的催化剂。这些成本相对较低的材料可以以纳米级的形式生产，其表面积高达200平方米/克，已被证明对许多工业上重要的反应具有活性，包括水气转换和烷烃异构化，并且具有热稳定性和化学稳定性。纳米级早期过渡金属碳化物和氮化物基催化剂的设计将从更好地理解它们的结构、组成和功能性质之间的关系中受益匪浅。本研究的目的是通过两种商业上相关的测试反应，水气转换（WGS）和费托合成（FTS），阐明控制早期过渡金属碳化物和氮化物催化性能的关键结构和组成特征。为完成项目目标，将采用的主要技术是超高分辨率透射电子显微镜（TEM）和原位x射线吸收光谱（XAS）。TEM和XAS结果将由红外光谱和x射线光电子能谱结果补充。这项工作是响应催化和生物催化计划的目标，支持在纳米尺度上功能的催化剂的合成和表征的多学科研究。纳米碳化物和氮基催化剂的潜在应用包括通过FTS生产氢气和“绿色汽油”，因此该项目支持与能源多样性和减少温室气体排放有关的努力。所提出的研究的知识价值在于对早期过渡金属碳化物和氮化物催化剂的知识库进行了显著的扩展。虽然这些材料催化反应的数据库不断增长，但关于它们的结构、组成和功能之间关系的基本信息却很少。超高分辨率的透射电镜将允许，也许是第一次，在催化剂的金属原子基体中的非金属原子的高分辨率成像。此外，XAS是为数不多的就地方法之一，它将提供发展明确的相互关系所需的成分、结构和电子信息。在提议的研究中得出的关系将大大提高我们对碳化物和氮化物特性的基本理解，并可以促进它们作为催化剂和催化剂支持的设计和开发，用于各种化学品和燃料的可持续生产。就更广泛的影响而言，拟议的研究将让代表性不足的少数民族高中生、本科生和研究生参与社会相关研究。拟议的项目将利用正在进行的教育和推广活动，包括密歇根-路易斯斯托克斯少数民族参与联盟和本科生研究机会计划。通过密歇根大学化学科学教育接口（CSIE）计划的扩展，本科和博士后化学工程和材料科学专业的学生将能够在他们的专业学习中增加教育。此外，通过与IDEA研究所的合作，来自底特律和伊普斯兰蒂学区的教师将参与以显微镜和表面科学为重点的夏令营项目，这两个学区都有大量得不到充分教育的学生。参与拟议项目的研究人员长期致力于增加代表性不足的群体参与真正的研究并将研究纳入教育活动。

0933239 Thompson Early transition metal (Group IV-VI) carbides and nitrides are a fascinating class of materials with a broad range of potential applications including use as catalysts for energy and environmentally sustainable processes. These relatively low cost materials can be produced in nanoscale form with surface areas as high as 200 m2/gr, have been demonstrated to be active for a number of industrially significant reactions including water gas shift and alkane isomerization, and are thermally and chemically stable. The design of nanoscale early transition metal carbide- and nitride-based catalysts would benefit significantly from a better understanding of relationships between their structural, compositional and functional properties. The goal of this research is to elucidate key structural and compositional features that govern the catalytic properties of early transition metal carbides and nitrides using two commercially relevant test reactions, the water gas shift (WGS) and Fischer-Tropsch Synthesis (FTS). The principal techniques that will be employed to accomplish the project goal are ultrahigh resolution transmission electron microscopy (TEM) and in situ x-ray absorption spectroscopy (XAS). The TEM and XAS results will be complemented by results from infrared spectroscopy and x-ray photoelectron spectroscopy. This effort is responsive to the Catalysis and Biocatalysis Program goal of supporting multidisciplinary research on the synthesis and characterization of catalysts that function at the nanoscale. Potential applications for nanoscale carbide- and nitride-based catalysts include the production of hydrogen and "green gasoline" via FTS, and consequently the project supports efforts related to energy diversity and reductions in greenhouse gas emissions. The intellectual merit of the proposed research lies in a significant expansion of the knowledge base for early transition metal carbide and nitride catalysts. While the database of reactions catalyzed by these materials has grown, there is little fundamental information about relationships between their structure, composition and function. The ultrahigh resolution TEM will allow, perhaps for the first time, high resolution imaging of the non-metal atoms in the metal atom matrix of the catalyst. In addition, XAS, one of only a few in situ methods, will provide the type of compositional, structural and electronic information needed to develop unambiguous correlations. Relationships derived during the proposed research will significantly enhance our fundamental understanding of the character of carbides and nitrides, and could facilitate their design and development as catalysts and catalyst supports for the sustainable production of a variety of chemicals and fuels. With regard to the broader impacts, the proposed research will engage under-represented minority high school, undergraduate and graduate students in socially relevant research. The proposed project will leverage on-going education and outreach activities including the Michigan-Louis Stokes Alliance for Minority Participation and Undergraduate Research Opportunity Program. Through an expansion of the University of Michigan Chemical Sciences at the Interface of Education (CSIE) program, undergraduate and post-doctoral chemical engineering and materials science students will be able to add education to their professional studies. In addition, through a collaboration with the IDEA Institute, teachers from the Detroit and Ypsilanti School Districts, both of which have large populations of underserved students, will be engaged in summer camp programs focused on microscopy and surface science. Researchers engaged in the proposed project have long-standing commitments to increasing the participation of underrepresented groups in authentic research and integrating research into educational activities.