Dynamic nuclear polarization at 7 Tesla to enable and enhance the study of chemical structures and surfaces

有了这个奖项，在化学系的化学测量和成像计划正在支持Song-I Han教授在加州大学圣巴巴拉分校追求先进的仪器和方法的开发，利用固态动态核极化（ssDNP）增强在7特斯拉和液氦温度显着增强核磁共振（NMR）信号。拟议的研究活动旨在提供高达4至5个数量级的NMR信号增强。 如果成功的话，这种新设备将能够以一种以前不可行的方式表征界面和表面。因此，拟议研究的最大影响在于表征社会感兴趣的化学系统和材料; namley，催化剂和能源相关和/或生物相容性材料。这项研究还为下一代研究生和本科生提供了跨学科的培训机会，为他们提供了从零开始的技术和硬件开发实践经验。总体研究目标是推进ssDNP增强NMR作为化学表征工具，重点是解决纳米尺度域和固体表面的局部特征，化学过程发生的地方，对材料功能至关重要。所提出的工作的智力价值是通过研究DNP增强的温度和微波功率依赖性，频率分布和建立时间曲线，以及电子和核自旋弛豫时间，来解决ssDNP性能的基本障碍和机制。将研究从纳米结构水凝胶、介孔催化剂到负载型催化剂的当代化学体系，目的是选择性地表征表面特征和空间异质性溶质/溶剂组合物。DNP的前景是很有希望的，它将NMR从提供原子细节，但在整个样品上平均，转变为表面敏感和选择性的工具。

With this award, the Chemical Measurement and Imaging Program in the Division of Chemistry is supporting Professor Song-I Han at the University of California-Santa Barbara to pursue the development of advanced instrumentation and methodologies to exploit solid-state dynamic nuclear polarization (ssDNP) enhancement at 7 Tesla and liquid helium temperatures to significantly enhance the nuclear magnetic resonance (NMR) signal. The proposed research activities is desigend to provide up to 4 to 5 orders of magnitudes of NMR signal enhancement. If successful, this new apparatus will enable characterization of interfaces and surfaces in a way not feasible before. Consequently, the largest impact of the proposed research lies in the characterization of chemical systems and materials of interest to society; namley, catalysts and energy-related and/or biocompatible materials. The proposed research also offers interdisciplinary training opportunities to next generation graduate and undergraduate students by providing them with hands-on experience in technology and hardware development from the ground up.The overarching research goal is to advance ssDNP-enhanced NMR as a chemical characterization tool, with the focus on resolving local signatures of nanometer-scale domains and solid surfaces, where chemical processes occur and that are critical for material function. The intellectual merit of the proposed work is to address fundamental roadblocks in and mechanisms of ssDNP performance via studies of the temperature and microwave power dependence of DNP enhancements, frequency profiles and build-up time curves, as well as electron and nuclear spin relaxation times. Contemporary chemical systems from nanostructured hydrogels, mesoporous catalysts to supported catalysts will be studied, with the aim of selectively characterizing surface signatures and spatially heterogeneous solute/solvent composition. The prospect for DNP to transform NMR from offering atomistic details, but averaged over the entire sample into a surface sensitive and selective tool, is promising.