標題: Dealloyed Pt2Os nanoparticles for enhanced oxygen reduction reaction in acidic electrolytes
作者: Lee, Yi-Juei
Hsieh, Yu-Chi
Tsai, Ho-Cheng
Lu, I-Te
Wu, Yue-Han
Yu, Ted H.
Lee, Jyh-Fu
Merinov, Boris V.
Goddard, William A., III
Wu, Pu-Wei
材料科學與工程學系
Department of Materials Science and Engineering
關鍵字: Oxygen reduction reaction;Platinum;Osmium;Dealloying process;Quantum mechanics
公開日期: 5-五月-2014
摘要: Carbon-supported Pt2Os (Pt2Os/C) nanoparticles in 3.55 nm sizes are synthesized from a wet chemical reflux process. Subsequently, the Pt2Os/C undergoes a dealloying treatment in which multiple cyclic voltammetric scans are imposed 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. This agrees with our quantum mechanics (Density Funtional theory) calculations, which predict for the Pt3Os composition that the surface skin layer is pure Pt. The DA-Pt2Os/C shows impressive electrocatalytic behaviors (0.29 mA mu g(Pt)(-1) in mass activity and 1.03 mA cm(Pt)(-2) in specific activity) for the 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/C. In stability test, the DA-Pt2Os/C demonstrates a better retention of ORR activities and a smaller loss of electrochemical active surface area. We verify experimentally that a four-electron step is responsible for the ORR process occurring on the DA-Pt2Os/C. (C) 2014 Elsevier B.V. All rights reserved.
URI: http://dx.doi.org/10.1016/j.apcatb.2014.01.004
http://hdl.handle.net/11536/23938
ISSN: 0926-3373
DOI: 10.1016/j.apcatb.2014.01.004
期刊: APPLIED CATALYSIS B-ENVIRONMENTAL
Volume: 150
Issue: 
起始頁: 636
結束頁: 646
顯示於類別:期刊論文


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