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

0933239汤普森早期过渡金属(第四至第六组)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进程的催化剂。这些成本相对较低的材料可以以纳米级的形式生产，比表面积高达200m2/gr，已被证明对包括水煤气变换和烷烃异构化在内的许多重要工业反应具有活性，并且具有热稳定性和化学稳定性。更好地了解纳米级早期过渡金属碳化物和氮化物催化剂的结构、组成和功能特性之间的关系，将对其设计产生重大影响。这项研究的目的是利用两个商业上相关的测试反应，即水煤气变换(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。实现该项目目标的主要技术是超高分辨率电子显微镜和原位X射线吸收光谱。透射电子显微镜和X射线光电子能谱的结果将与红外光谱和X射线光电子能谱的结果相补充。这一努力是为了响应催化和生物催化计划的目标，即支持在纳米级起作用的催化剂的合成和表征的多学科研究。纳米碳化物和氮化物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。这项研究的智力价值在于极大地扩展了早期过渡金属碳化物和氮化物催化剂的知识库。虽然这些材料催化的反应数据库已经扩大，但关于它们的结构、组成和功能之间的关系的基本信息很少。超高分辨率的电子显微镜可能首次实现催化剂金属原子基质中非金属原子的高分辨率成像。此外，XAS是为数不多的几种原位方法之一，它将提供建立明确相关性所需的成分、结构和电子信息。在拟议研究期间得出的关系将大大加强我们对碳化物和氮化物特性的基本了解，并可促进它们的设计和开发，使其成为各种化学品和燃料可持续生产的催化剂和催化剂载体。关于更广泛的影响，拟议的研究将使未被充分代表的少数族裔高中、本科生和研究生参与与社会相关的研究。拟议的项目将利用正在进行的教育和外联活动，包括密歇根-路易斯·斯托克斯少数群体参与联盟和本科生研究机会计划。通过扩大密歇根大学化学科学教育接口(CSIE)计划，本科生和博士后化学工程和材料科学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，底特律和伊普西兰蒂学区的教师将参加专注于显微镜和表面科学的夏令营项目。底特律和伊普西兰蒂学区都有大量服务不足的学生。参与拟议项目的研究人员长期致力于让代表性不足的群体更多地参与真实研究，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.