Development of Platinum and Platinum-Nickel Catalysts for Fuel Cell Applications

• Author / Creator

  Francis,Sonja A

• This dissertation describes the use of a novel Pt deposition to prepare nickel- and carbon-supported platinum catalysts. The deposition is referred to herein as the platinum counter electrode deposition. The source of platinum is the sacrificial dissolution of a blacked platinum counter electrode under galvanostatic conditions that results in conformal, ultra-low loadings of platinum onto the substrates. It is shown that all or most of the platinum is located at the surface of the catalyst in the case where Pt is co-deposited with nickel from a solution of its salt. Furthermore, the deposition is self-limiting. Four major studies based on catalysts synthesized by this method are presented.
  
  The opening study describes the deposition of platinum and co-deposition of platinum and nickel onto nickel foam substrates as well as the electronic and microscopic characteristics of the deposits. Further, the activity of the prepared catalysts towards 2-propanol oxidation in base was explored. Above 500 mV, the nickel and platinum co-deposit on nickel foam was 9 times more active than blackened Pt gauze, while the platinum deposit on nickel foam was 38 times more active.
  The second study compares a conventional platinum deposition with the platinum counter electrode deposition on nickel nanopillar films prepared by Glancing Angle Deposition. The deposits prepared via our method were more active towards 2-propanol oxidation than both traditionally prepared deposits and commercially available state-of-the-art unsupported platinum nanoparticles.
  The same nanopillar-supported platinum catalysts were prepared on glassy carbon disks for the third study. Activity towards oxygen reduction in base and acid was investigated. This is the first oxygen reduction study on nickel-platinum glancing angle deposited structures and the first such study in basic media.
  The ultimate study describes the modification of the platinum counter electrode deposition to accommodate particulate substrates. As a proof of concept, we deposited platinum onto Vulcan carbon to fabricate a carbon-supported platinum catalyst that was microscopically and electrochemically characterized and tested for oxygen reduction. The results of this study suggest the utility of this deposition for a variety of particulate conductive substrates.

• Subjects / Keywords

  • Nickel
  • 2-propanol
  • Glancing angle deposition
  • Platinum
  • Direct alcohol fuel cell

• Graduation date

  Fall 2013

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3MD6V

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.