Thesis
Effect of different synthesis of CU@PD/C core@shell nanoparticles used to fabricate toward the formic acid electrochemical oxidation
Washington State University
Master of Science (MS), Washington State University
2017
Handle:
https://hdl.handle.net/2376/103274
Abstract
Direct formic acid fuel cells (DFAFCs) use anode catalysts based on precious metals such Pd. Unfortunately, Pd has poor stability, and it can be poisoned easily by poisoning species like CO. The catalyst poisoning leads to poor stability and efficiency of DFAFCs. Therefore, it is important to develop new catalysts that are more stable and less expensive than Pd for DFAFCs. By designing the core@shell structured nanoparticles of non-expensive 3d transition metals as core and the Pd as the shell, the electro-catalytic property of Pd surface can be preciously tuned. This leads to a change in adsorption energy of intermediate species during the electro-oxidation of formic acid on the Pd surface. The research goal is to achieve an optimum bond strength by selecting a proper 3d transition metal core. The studies on the core@-shell structured bimetallic catalysts have resulted in better fuel cell performances than that of pure Pd. Among them, Cu@Pd prepared by the two-step successive reduction method showed the best initial and long-term stability performances. In the present study, Cu@Pd/C were prepared by two different methods: two-step reduction successive method and adsorbate-induced surface segregation method. Two-step successive reduction and sdsorbate-induced surface segregation methods lead to Cu@Pd/C nanoparticle samples with the average size of the 6.22 nm and 6.27 nm, respectively. XPS data illustrate that the Pd 3d5/2 shifts positively to higher binding energy (BE) and the d-band center moves away from the Fermi level for both Cu@Pd/C samples compared to that of Pd/C. Changing in the BE and d-band center indicate that the electronic structure of the Pd surfaces are modified for both Cu@Pd/C samples, which resulted in improved activity and stability toward the formic acid oxidation reaction.
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Details
- Title
- Effect of different synthesis of CU@PD/C core@shell nanoparticles used to fabricate toward the formic acid electrochemical oxidation
- Creators
- Bita Khorasani
- Contributors
- Su Ha (Degree Supervisor)Louis Scudiero (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Chemical Engineering and Bioengineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525007401842
- Language
- English
- Resource Type
- Thesis