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.
