Wiesner Group

A fuel cell is a system that directly converts chemical energy to electric energy via two electrochemical half reactions:

Anode reaction: H2 -> 2H+ + 2e- (oxidation)

Cathode reaction: ½ O2 + 2H+ + 2e- -> H2O (reduction)

The two ‘half-cells’ are spatially separated (e.g., by a polymer electrolyte membrane/ proton exchange membrane) and the flow of electrons from the anode to the cathode can be used to do useful work.

For optimal performance, the reaction surface area is maximized by fabricating highly porous, nano-structured electrodes to achieve intimate contact between gas-phase pores, the electro-catalyst , the electrically conductive electrode and the ion-conductive electrolyte.

This reaction site is known as the Triple Phase Boundary highlighted in yellow in the image at left.

By using block copolymers as structure directing agents, we can make mesostructured materials which allows for better mass transport of fuel/ oxidant through the electrodes.

This only satisfies one requirement for the triple phase boundary condition but it provides the foundation upon which our current research is based on, i.e., designing better materials for use as electrodes in PEMFCs.

An example of our initial work on catalyst supports is shown at right with catalytic nanoparticles isolated within the aluminosilicate pore network.

Selected References:

J. Lee, M. Orilall, S. Warren, M. Kamperman, F. DiSalvo, U.Wiesner. "A Soft-Hard Integrated Assembly Method to Thermally Stable, Fully Crystalline Mesoporous Transition Metal Oxides with Large, Uniform Pores." Nature Materials (2008)

C. Roychowdhury, F. Matsumoto, V. B. Zeldovich, S. C. Warren, P. F. Mutolo, M. Ballesteros, U. Wiesner, H. D. Abruna, F. J. DiSalvo, "Synthesis, Characterization, and Electrocatalytic Activity of PtBi and PtPb Nanoparticles Prepared by Borohydride Reduction in Methanol", Chem. Mater. 18, 2006, 3365-3372

O’Hayre, R., et. al. Fuel Cell Fundamentals. John Wiley & Sons, N.Y., 2006

Cornell Fuel Cell Institute