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Robust Platinum-Based Electrocatalysts for Fuel Cell Applications

Coleman, Eric James
http://rave.ohiolink.edu/etdc/view?acc_num=osu1437484946

Abstract Details

2015, Doctor of Philosophy, Ohio State University, Chemistry.
Polymer electrolyte fuel cells (PEMFCs) are energy conversion devices that exploit the energetics of the reaction between hydrogen fuel and O2 to generate electricity with water as the only byproduct. PEMFCs have attracted substantial attention due to their high conversion efficiency, high energy density, and low carbon footprint. However, PEMFC performance is hindered by the high activation barrier and slow reaction rates at the cathode where O2 undergoes an overall 4-electron reduction to water. The most efficient oxygen reduction reaction (ORR) catalyst materials to date are Pt group metals due to their high catalytic activity and stability in a wide range of operating conditions. Before fuel cells can become economically viable, efforts must be taken to decrease Pt content while maintaining a high level of ORR activity. This work describes the design and synthesis of a Pt-Cu electrocatalyst with ORR activity exceeding that of polycrystalline Pt. Production of this novel catalyst is quite simple and begins with synthesis of a porous Cu substrate, formed by etching Al from a Cu-Al alloy. The porous Cu substrate is then coated with a Pt layer via a spontaneous electrochemical process known as galvanic replacement. The Pt layer enhances the ORR activity (as measured by a rotating ring-disk electrode (RRDE)) and acts as a barrier towards corrosion of the Cu understructure. Growth of the Pt layer can be manipulated by time, temperature, concentration of Pt precursor, and convection rate during galvanic replacement. Data from analytical and electrochemical techniques confirm multiple Pt loadings have been achieved via the galvanic replacement process. The boost in ORR activity for the PtCu catalyst was determined to be a result of its lower affinity towards (site-blocking) OH adsorption. A unique catalyst degradation study explains the mechanism of initial catalyst ORR deactivation for both monometallic and bimetallic Pt-based catalysts. Finally, a rigorous and pioneering examination of how Pt surface passivation affects ORR dynamics is presented.
Anne Co, Ph.D (Advisor)
Prabir Dutta, Ph.D (Committee Member)
Umit Ozkan, Ph.D (Committee Member)
Lawrence Baker, Ph.D (Committee Member)
205 p.
Chemical Engineering; Chemistry; Energy
fuel cells; electrocatalysis; catalysis; platinum-based; bimetallic catalysts; oxygen reduction

Recommended Citations

Citations

  • Coleman, E. J. (2015). Robust Platinum-Based Electrocatalysts for Fuel Cell Applications [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437484946

    APA Style (7th edition)

  • Coleman, Eric. Robust Platinum-Based Electrocatalysts for Fuel Cell Applications. 2015. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1437484946.

    MLA Style (8th edition)

  • Coleman, Eric. "Robust Platinum-Based Electrocatalysts for Fuel Cell Applications." Doctoral dissertation, Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437484946

    Chicago Manual of Style (17th edition)

osu1437484946
558
© 2015, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.