| Summary: | 碩士 === 國立臺灣師範大學 === 化學系 === 106 === The present study includes two main parts: the cathodic oxygen reduction reaction （ORR） and anodic ethanol oxidation reaction （EOR） on PtSn bimetallic catalysts. In the study of ORR, PtSn catalyst was modeled by Pt （111）surface with varied Sn substitution of surface Pt. Our calculations found that the more Sn substitution results the higher activity, attributable to their lower oxophilicity and d-band center of adjacent Pt; however, the more Sn substitution demotes the stability due to the structural distortion. The durability can be further improved by separating and lifting the oxide phase of Sn on Pt surface. The oxide has moderate adsorption on Pt surface and strong repulsion among them to retain the structure during ORR. In the study of EOR, we modified PtSn bimetal with the addition of Ag forming ternary PtSnAg catalyst. The oxide phase of Ag can effectively enhance CH3CHO oxidize to CH3COOH, the key step, and promote EOR activity due to its attraction of dissociated H and repulsion of OH. Additionally, the oxide can assist ethanol adsorption on the neighboring Pt that can lower the initial dehydrogenation step.
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