Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Science

Program

Chemistry

Supervisor

Sham, Tsun-Kong

2nd Supervisor

Sun, Xueliang

Joint Supervisor

Abstract

Polymer electrolyte membrane fuel cell (PEMFC), is considered a promising candidate for the next generation power sources in transportation, stationary and portable applications. However, oxygen reduction reaction (ORR), one of the key reactions occurring on PEMFC is kinetically slow; this has limited performance and further advancement in this kind of fuel cells. Thus, improving the PEMFC efficiency requires a thorough understanding of the ORR mechanism on the desired catalyst. To address the above-mentioned demands, the scope of this thesis is focused on the fundamental understanding of facet-controlled nanoparticles, metal-support interactions, and bimetallic platinum catalysts, utilizing synchrotron-based X-ray absorption, X-ray photoelectron spectroscopy, and electrochemical characterization methods.

It is found that particle size, shape, composition (Pd and Co are the other metals), and the supporting material not only can act as momentous parameters in enhancing the catalytic activity of NPs but also are functioning as vital criteria in boosting the stability.

Summary for Lay Audience

Climate change and deficiency of petroleum-based energy resources have risen concerns about the future of planet earth and have made scientist to be more focused on fuel cell technologies, due to their low emissions and high efficiencies. Low operation temperature, high power, and energy density have made the PEMFC, a promising candidate for the next generation power sources in transportation, stationary and portable applications. Low abundance, limited supply, and increasing demand have limited the commercial application of Pt, as a critical catalytic component in PEMFC. So finding out an efficient catalyst and substituting it with the current commercial ones can accelerate the utilization of this technology and can cease the current concerns about the climate change crises. DFAFCs as a subcategory of PEM fuel cells have also attracted lots of attentions in recent years due to their high energy conversion efficiency and non-toxic and safe fuel. The low stability of palladium, as a catalyst for DFAFC has also diminished its commercial applications and catalysts with higher stability will be required. This study will discuss more fundamentally the ways for satisfying the mentioned demands.

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