| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 101 === This study focuses on activity improvement for the anode catalysts in direct ethanol fuel cells. According to literatures, the catalyst with the highest activity for ethanol oxidation is platinum-tin alloy. This research investigated the effects of atomic ratio of platinum to tin, synthesis methods, appropriate third metal and atomic ratio for ternary alloy on the catalyst activity which was used to determine. the best anode catalyst for direct ethanol fuel cell.
For the binary alloy catalysts,only Pt-Sn/C gave a clear peak current at 0.4V (vs. Ag / AgCl) in a cyclic voltammogram, and the other metals only gave the peak current in 0.7V (vs. Ag / AgCl). The infrared spectrum confirmed that the reaction of Pt-Sn/C at 0.4V (vs. Ag / AgCl) is due to the oxidation of ethanol to acetaldehyde . The atomic ratio of Pt/Sn 1:1 had the highest activity.
This study not only focused on the impregnation reduction method but also utilized displacement method. Tin reduced platinum precursor on the tin surface to provide greater surface area on platinum , as confirmed in half cell test. The catalysts formed by displacement method have higher activity(39.4 mA/mg Pt) than impregnation reduction method. But in single cell test, the enhancement of catalysts activity was not significant.
Comparing to palladium and nickel, ruthenium is more suitable as the third metal for ternary alloy catalysts, because the If/Ib of the platinum-ruthenium alloy was larger than those of others, due to the enhancement of anti-poisoning of the catalyst. And this study found that the ternary alloy with atomic ratio of Pt: Sn: Ru = 1:1:0.5 gavethe highest activity. The product analysis from a single cell also proved that ternary alloy increased the oxidation of ethanol to carbon dioxide.
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