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The electrodeposition and electrochemical properties of nanostructured (H1-e) metal films

The electrodeposition and electrochemical properties of nanostructured (H1-e) metal films
The electrodeposition and electrochemical properties of nanostructured (H1-e) metal films

Electrochemical deposition of metals from hexagonal lyotropic liquid crystalline phases produces metal films with a unique ordered nanostructure in which the cylindrical pores of 1.7 to 3.5 nm running through the film are arranged in hexagonal arrays.

Nanostructured Pd and Rh films were deposited electrochemically from the template mixture of either C16EO8 or Brij(r)56. Electrochemical studies showed that both metal films have a high electroactive surface area with the specific surface area of the order of 91 and 32 m2/g, respectively. These values together with the TEM and X-ray data are consistent with the expected H1 nanostructure.

The hydrogen region of nanostructured Pd in the cyclic voltammetry in 1 M H2SO4 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 the adsorbed hydrogen is suppressed by the coverage of poisons.

Nanostructured Pd was used as catalyst for methane oxidation in gas sensors. Pluronic F127 was found to be a suitable surfactant in the template mixture giving a far less viscous phase.

Electrochemical studies of nanostructured Rh films showed the surface oxide stripping peak on the cathodic scan moving towards positive potentials on potential-cycling attributable to changes in the surface oxide states. The peaks in the hydrogen region became better resolved on increasing the number of voltammetric cycles. Nanostructured Rh films were used for the electroreduction of nitrate and showed greater sensitivity compared to Rh electrodes deposited from the aqueous solution and compared to nanostructured Pd and Pt films.

University of Southampton
Marwan, Jan
7a202e4d-1b98-409b-87d3-682cdf8fb964
Marwan, Jan
7a202e4d-1b98-409b-87d3-682cdf8fb964

Marwan, Jan (2002) The electrodeposition and electrochemical properties of nanostructured (H1-e) metal films. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

Electrochemical deposition of metals from hexagonal lyotropic liquid crystalline phases produces metal films with a unique ordered nanostructure in which the cylindrical pores of 1.7 to 3.5 nm running through the film are arranged in hexagonal arrays.

Nanostructured Pd and Rh films were deposited electrochemically from the template mixture of either C16EO8 or Brij(r)56. Electrochemical studies showed that both metal films have a high electroactive surface area with the specific surface area of the order of 91 and 32 m2/g, respectively. These values together with the TEM and X-ray data are consistent with the expected H1 nanostructure.

The hydrogen region of nanostructured Pd in the cyclic voltammetry in 1 M H2SO4 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 the adsorbed hydrogen is suppressed by the coverage of poisons.

Nanostructured Pd was used as catalyst for methane oxidation in gas sensors. Pluronic F127 was found to be a suitable surfactant in the template mixture giving a far less viscous phase.

Electrochemical studies of nanostructured Rh films showed the surface oxide stripping peak on the cathodic scan moving towards positive potentials on potential-cycling attributable to changes in the surface oxide states. The peaks in the hydrogen region became better resolved on increasing the number of voltammetric cycles. Nanostructured Rh films were used for the electroreduction of nitrate and showed greater sensitivity compared to Rh electrodes deposited from the aqueous solution and compared to nanostructured Pd and Pt films.

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Published date: 2002

Identifiers

Local EPrints ID: 464858
URI: http://eprints.soton.ac.uk/id/eprint/464858
PURE UUID: 7af1f195-1b83-4e5e-9113-01bcfc4c3f58

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Date deposited: 05 Jul 2022 00:05
Last modified: 05 Jul 2022 03:22

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Author: Jan Marwan

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