ENVR 233 |
| Electrochemical deposition of metals from hexagonal lyotropic liquid crystalline phases produces metal films with an unique ordered nanostructure in which the cylindrical pores of 1.7 to 3.5 nm running through the film are arranged in hexagonal arrays. Electrochemical studies showed that the metal films have a high electroactive surface area. These values together with the TEM and X-ray data are consistent with the expected nanostructure. The hydrogen region of nanostructured Pd in the cyclic voltammetry in 1 M sulfuric acid was more resolved than that of plain Pd because of the thin walls of the nanostructure and the high surface area. We could distinguish the hydrogen adsorption and absorption processes. The permeation of hydrogen into the Pd metal lattice occurs with fast kinetics when the Pd surface is blocked by either crystal violet or Pt. We believe that the hydrogen absorption process takes place without passing through the adsorbed state so that hydrogen diffuses directly into the Pd bulk. This process speeds up when the formation of adsorbed hydrogen is suppressed by the coverage of poisons. These results were compared to those obtained in a heavy water solution to which the Pd electrode was exposed. Adsorption characteristics of deuterium on the Pd metal surface are slightly different to those obtained for hydrogen in previous studies. Diffusion of deuterium into the Pd metal lattice works with fast kinetics under appropriate surface modification. |
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New Energy Technology
1:30 PM-3:00 PM, Thursday, March 29, 2007 McCormick Place South -- Room S106B, Level 1, Oral
Division of Environmental Chemistry |