Carbon Supported Pt-Os Electrocatalysts for Oxygen Reduction Reaction in Acidic Fuel Cells
碩士 === 國立交通大學 === 材料科學與工程學系所 === 101 === Carbon-supported Pt2Os (Pt2Os/C) nanoparticles in 3.1 nm size are synthesized from a wet chemical reflux process. Subsequently, the Pt2Os/C undergoes a dealloying treatment in which multiple cyclic voltammetric scans are imposed in a 50 mL of deaerated 0.1 M...
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| Format: | Others |
| Language: | en_US |
| Published: |
2013
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| Online Access: | http://ndltd.ncl.edu.tw/handle/47968490573744852110 |
| Summary: | 碩士 === 國立交通大學 === 材料科學與工程學系所 === 101 === Carbon-supported Pt2Os (Pt2Os/C) nanoparticles in 3.1 nm size are synthesized from a wet chemical reflux process. Subsequently, the Pt2Os/C undergoes a dealloying treatment in which multiple cyclic voltammetric scans are imposed in a 50 mL of deaerated 0.1 M aqueous HClO4 solution to dissolve the Os atoms selectively from the surface of the Pt2Os nanoparticles. X-ray diffraction signals from the dealloyed sample (DA－Pt2Os/C) indicate a fcc phase and composition analysis suggests Pt4Os. Line scans from the scanning transmission electron microscope confirm that the surface of Pt4Os is depleted with the Os atoms. The DA－Pt2Os/C shows impressive electrocatalytic behaviors (0.29 mA μgPt-1 in mass activity and 1.03 mA cmPt-2 in specific activity) for oxygen reduction reaction (ORR) in oxygen-saturated 0.1 M aqueous HClO4 solution, as compared to those of commercially available Pt/C and as-synthesized Pt2Os. In stability test, the DA－Pt2Os/C demonstrates better retention in ORR activities and smaller loss of electrochemical active surface area. In addition, a four-electron step is responsible for the ORR actions occurring on the DA－Pt2Os/C.
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