Nuclear Magnetic Resonance Investigations in Fuel Cell Catalysis

教授们。Eric Oldfield和Andrzej Wieckowski将发展原位高场核磁共振电化学(NMRE)技术来研究电催化剂中的界面结构和动力学，目的是阐明电极材料的改性在甲醇燃料电池铂催化剂中毒中的作用。在恒电位控制下，电化学电池中的金属表面和吸附结构都将被表征。在密度泛函计算的辅助下，Knight位移、自旋晶格和自旋-自旋弛豫时间的确定将与金属和吸附的费米能级LDO的位移相关联。特别是，这项研究将涉及获得LDOS(双金属颗粒将由铂与Ru、Sn、Rh或Cu组成)的燃料电池催化剂的195PT核磁共振，以及用于获得扩散动力学的吸附CO的13C和17O核磁共振。将确定催化剂-载体和催化剂-吸附物的相互作用，以及电极电位和电解液环境对表面结构和动力学的影响。这项研究的更广泛意义在于设计了抗CO中毒、高电流密度的甲醇氧化电极，这些电极在移动电源中具有潜在的用途。

Profs. Eric Oldfield and Andrzej Wieckowski will develop in-situ high-field nuclear magnetic resonance-electrochemistry (NMRE) techniques to investigate interfacial structure and dynamics in electrocatalysts, with the purpose of clarifying the role of modification of electrode material in the poisoning of Pt electrocatalysts for methanol fuel cells. Both metal surface and adsorbate structures in an electrochemical cell under potentiostatic control will be characterized. Knight shifts, spin-lattice and spin-spin relaxation times determination, aided with density-functional calculations, will be correlated with shifts of the Fermi-level LDOS of metal and adsorbates. In particular, the research will involve 195Pt NMR of fuel cell catalysts to obtain LDOS (bimetallic particles will be composed of Pt with Ru, Sn, Rh, or Cu); and 13C and 17O NMR of adsorbed CO to obtain diffusion kinetics. Determination will be made of catalyst-support and catalyst-adsorbate interactions; and of the effects of electrode potential and electrolyte environment on surface structure and dynamics. The wider relevance of the research is in the design of CO-poisoning resistant, high current-density electrodes for methanol oxidation, which have potential use in mobile power sources.