| AVS 55th International Symposium & Exhibition | |
| Nanometer-scale Science and Technology | Tuesday Sessions |
| Session NS-TuP |
| Session: | Poster Session |
| Presenter: | Y.E. Seidel, Ulm University, Germany |
| Authors: | Y.E. Seidel, Ulm University, Germany A. Schneider, Ulm University, Germany L. Colmenares, Ulm University, Germany Z. Jusys, Ulm University, Germany R.J. Behm, Ulm University, Germany B. Wickmann, Chalmers University of Technology, Sweden B. Kasemo, Chalmers University of Technology, Sweden |
| Correspondent: | Click to Email |
In this contribution, we discuss the potential of nanostructured planar electrodes for model studies of electrocatalytic reactions relevant for Polymer Electrolyte Fuel Cell (PEFCs). The model electrodes consist of catalytically active Pt nanostructures of well-defined size and separation, which are supported on planar glassy carbon substrates.1,2 They are fabricated employing colloidal lithography (CL)1 or Hole-mask Colloidal Lithography (HCL),2 or by micellar techniques, via deposition of metal loaded micelles and the subsequent removal of the polymer stabilizer.3 Both techniques allow us to independently vary size and separation of the catalytically active nanostructures/particles. The resulting particle sizes are ca. 3-15 nm (micellar techniques) and 70-150 nm (CL, HCL), respectively. These nanostructured model electrodes allow direct and quantitative access to an important aspect of electrocatalytic reactions which so far has been largely neglected, to the influence of mesoscopic transport effects on the characteristics of electrocatalytic reactions. Using the reduction of O2 and the oxidation of formaldehyde as examples it will be shown that mass transport effects not only modify the overall rate, but have significant effect also on the product distribution, e.g., on H2O2 formation. Possible contributions of the reactant transport to the overall reaction process will be discussed in a molecular picture.
1 M. Gustavsson, K. Fredriksson, B. Kasemo, Z. Jusys, J. Kaiser, C. Jun, and R.J. Behm, J. Electroanal. Chem. 568 (2004) 371.
2 H. Fredriksson, Y. Alaverdyan, A. Dmitiev, C. Langhammer, D.S. Sutherland, M. Zäch, B. Kasemo, Adv. Mater. 19 (2007) 4297.
3 Y.E. Seidel, R. Lindström, Z. Jusys, J. Cai, U. Wiedwald, P. Ziemann, R.J. Behm, Langmuir 23 (2007) 5795.