Nuclear Magnetic Resonance Investigations in Fuel Cell Catalysis

教授Eric Oldfield和Andrzej Wieckowski将开发原位高场核磁共振电化学（NMRE）技术，以研究电催化剂的界面结构和动力学，目的是澄清电极材料改性在甲醇燃料电池Pt电催化剂中毒中的作用。在恒电位控制下的电化学电池中的金属表面和吸附物结构将被表征。奈特位移，自旋-晶格和自旋-自旋弛豫时间的测定，辅助密度泛函计算，将与金属和吸附物的费米能级LDOS的位移。特别是，该研究将涉及燃料电池催化剂的195 Pt NMR以获得LDOS（催化剂颗粒将由Pt与Ru，Sn，Rh或Cu组成）;以及吸附CO的13 C和17 O NMR以获得扩散动力学。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质环境对表面结构和动力学的影响。更广泛的相关性的研究是在CO中毒的抗，高电流密度的甲醇氧化电极的设计，这在移动的电源有潜在的用途。

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.