CAREER: Solid State NMR Studies of Transition Metal Oxides: Correlation of Local Structure with Physical Properties

本项目将研究控制结构扭曲的因素，以改变介孔氧化物和剥离纳米片的表面酸性，以智能地定制这些材料的反应活性，这些材料有可能用作催化剂、质子导体和新型纳米结构材料的构建块。其目的是测量金属氧化物局部结构与这些材料的观察到的表面性质之间的相关性。为了建立这种关联，采用了固体核磁共振方法，以早期过渡金属钛-47、49和Nb-93的核磁共振活性同位素为重点。基于四极核检测到的电场梯度和化学位移各向异性，两者都是由金属周围原子的排列和键合产生的，信息被用来确定以金属为中心的多面体的局部对称性。双共振核磁共振方法将金属原子与吸附物种中的相邻元素关联起来，以区分表面位置并探索表面位置的相互作用强度。该项目将介绍和培训本科生和研究生与材料科学研究相关的问题和方法。P.I正在开发材料科学课程，包括课程和实验室，以增加克拉克大学本科生和研究生课程中材料化学的曝光率，方法是开设固体化学、衍射学的高级课程，并在入门化学中纳入固体化学实验模块。有关高表面积材料的结构和表面的详细信息，如介孔氧化物和剥离纳米片，对于提高它们作为催化剂、质子导体和新型纳米结构材料的构建块的性能是必要的。本项目的目的是通过固体核磁共振方法探测高比表面积剥离或介孔氧化物中的Nb和钛环境，表征这些材料的金属氧化物局域结构与观察到的表面性质之间的相关性。这些结果将为优化高比表面积纳米材料的反应表面结构提供指导。该项目将介绍和培训本科生和研究生与材料科学研究相关的问题和方法。P.I.正在开发材料科学课程，包括课程和实验室，以增加克拉克大学本科生和研究生课程中材料化学的曝光率，方法是开设固体化学、衍射学的高级课程，并在入门化学中纳入固体化学实验模块。P.I.正在与克拉克大学学术进步办公室合作，指导Alana(非裔美国人、拉丁裔、亚裔和原住民)和第一代学生在化学领域的研究机会和职业要求。

AbstractThis project will investigate factors that control the structural distortions necessary to alter the surface acidity of mesoporous oxides and exfoliated nanosheets to intelligently tailor the reactivity of these materials which have the potential to serve as catalysts, proton conductors, and building blocks for novel nanostructured materials. The goal is to measure the correlation between the metal oxide local structure and the observed surface properties of these materials. To develop this correlation, solid-state Nuclear Magnetic Resonance (NMR) methodologies are employed using the NMR active isotopes of early transition metals, titanium-47, 49 and niobium-93, as the focal point. Information based on the electric field gradient sensed by a quadrupolar nucleus and the chemical shift anisotropy, both created by the arrangement and bonding of atoms surrounding the metal, is used to determine the local symmetry of the metal-centered polyhedra. Double resonance NMR methods correlate the metal atoms with adjacent elements present in adsorbed species to distinguish surface sites and probe the interaction strengths of the surface sites. The project will introduce and train undergraduate and graduate students in the issues and methods associated with materials science research. The P.I is developing materials science curricula, both courses and labs, to increase the exposure of materials chemistry in the undergraduate and graduate programs at Clark University through the establishment of upper-level courses in solid-state chemistry, diffraction, and the incorporation of solid-state chemistry lab modules in introductory chemistry.%%%Detailed information about the structure and surface of high surface area materials, such as mesoporous oxides and exfoliated nanosheets, is necessary to improve their performance as catalysts, proton conductors, and building blocks for novel nanostructured materials. The aim of this project is to characterize the correlation between the metal oxide local structures and the observed surface properties of high surface area exfoliated or mesoporous oxides through solid-state NMR methods that probe the niobium and titanium environments in these materials. These results will serve as a guide for optimization of reactive surface structures in high surface area nanomaterials. The project will introduce and train undergraduate and graduate students in the issues and methods associated with materials science research. The P.I. is developing materials science curricula, both courses and labs, to increase the exposure of materials chemistry in the undergraduate and graduate programs at Clark University through the establishment of upper-level courses in solid-state chemistry, diffraction, and the incorporation of solid-state chemistry lab modules in introductory chemistry. The P.I. is working with the Academic Advancement Office of Clark University to mentor ALANA (African American, Latino, Asian and Native American) and first generation students on the research opportunities available and the requirements of careers in chemistry.