Masters Thesis

Catalysts for Electrochemical Oxidation of Renewable Fuels

A variety of alternative renewable fuels have been demonstrated on various catalyst surfaces that can be employed in alkaline direct liquid fuel cells (DLFCs). Palladium is an efficient catalyst for alcohol oxidation; however the oxidation rates for polyalcohols are slow to progress. Therefore, several ratios of PdxCuy/C (Pd63Cu37/C, Pd46Cu54/C, Pd28Cu72/C, Pd 11Cu89/C), PdxNiy/C (Pd16Ni 84/C, Pd53Ni47/C, Pd68Ni32/C) and Pd/C were synthesized and characterized for the electrochemical oxidation of ethylene glycol (EG), propylene glycol (PG), and glycerol (G). the greatest promotion for the oxidation of EG was observed on Pd28Cu72 /C (7 times faster than Pd/C), for PG on Pd11Cu89/C (12 times), and for G on Pd63Cu37/C (14 times). Furthermore, PG oxidation rate was enhanced 14 times on a Pd53Ni47/C catalyst. a significant shift in d-band center and an increase in hydroxyl adsorption at lower potentials were observed on each PdxCu y/C and PdxNiy/C catalyst compared to that of Pd/C. Therefore, the observed oxidation rate enhancements are due to the combination of the electronic effect and bifunctional effect. Ascorbic Acid (Vitamin C), an environmentally and biologically friendly compound was also investigated as a renewable alternative fuel. This study reports a direct ascorbate fuel cell that produced a maximum power density of 73 mW cm-2 with Pd and improved to 89 mW cm-2 with Pd28Cu72 /C as the anode catalysts. in addition, this work demonstrates an operating ascorbate fuel cell that does not require metal catalysts by simply using carbon black nanoparticles at each electrode.

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