A Combinatorial Approach For Exploring Fuel Cell Electrocatalysts
Fuel cells represent an alternative energy technology with the potential for providing more efficient means for energy conversion. However, their widespread deployment has been hampered by materials limitations, especially for the catalysts as they can be expensive, easily poisoned, and/or unstable over time. In order to accelerate the discovery and development of electrocatalysts that enhance fuel cell performance, a high throughput method is employed to screen many compositions and phases simultaneously. Preparation of the composition-spread libraries is achieved via cosputtering of multiple elements onto a Ta- or Ti-coated 3-inch Si wafer. These samples are screened as anode electrocatalysts using a fluorescence assay with quinine as the fluorescent probe. A key development is the characterization of these thin films via X-ray diffraction at Cornell's High Energy Synchrotron Source (CHESS). Systems of interest are discussed, including Pt-Zn, Pt-Ta, Pt-M alloys (M= transition metal at concentrations below 40%). Compositions exhibiting promising activity for specific fuels in the fluorescence tests are further characterized using a scanning electrochemical minicell. Alternative materials are introduced, i.e. nitrides and carbides, as well as non-Pt containing metal compositions. Fundamental studies on understanding fuel oxidation in neutral pH are described and further development of the fluorescence screening methodology for the cathode is presented.
Methanol oxidation; fuel cells; Platinum alloys; combinatorial screening; Fluorescence; high throughput
Abruna, Hector D
Disalvo, Francis J; Van Dover, Robert B.
Chemistry and Chemical Biology
Ph. D., Chemistry and Chemical Biology
Doctor of Philosophy
dissertation or thesis