Lee, Yi-Juei and Hsieh, Yu-Chi and Tsai, Ho-Cheng and Lu, I-Te and Wu, Yue-Han and Yu, Ted H. and Lee, Jyh-Fu and Merinov, Boris V. and Goddard, William A., III and Wu, Pu-Wei (2014) Dealloyed Pt_(2)Os nanoparticles for enhanced oxygen reduction reaction in acidic electrolytes. Applied Catalysis B, 150-151 . pp. 636-646. ISSN 0926-3373. http://resolver.caltech.edu/CaltechAUTHORS:20140421-104729502
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Abstract
Carbon-supported Pt2Os (Pt_(2)Os/C) nanoparticles in 3.55 nm sizes are synthesized from a wet chemical reflux process. Subsequently, the Pt_(2)Os/C undergoes a dealloying treatment in which multiple cyclic voltammetric scans are imposed to dissolve the Os atoms selectively from the surface of the Pt_(2)Os nanoparticles. X-ray diffraction signals from the dealloyed sample (DA–Pt_(2)Os/C) indicate a fcc phase and composition analysis suggests Pt4Os. Line scans from the scanning transmission electron microscope confirm that the surface of Pt_(4)Os is depleted with the Os atoms. This agrees with our quantum mechanics (Density Funtional theory) calculations, which predict for the Pt_(3)Os composition that the surface skin layer is pure Pt. The DA–Pt_(2)Os/C shows impressive electrocatalytic behaviors (0.29 mA μgPt^(−1) in mass activity and 1.03 mA cmPt^(−2) in specific activity) for the oxygen reduction reaction (ORR) in oxygen-saturated 0.1 M aqueous HClO_4 solution, as compared to those of commercially available Pt/C and as-synthesized Pt_(2)Os/C. In stability test, the DA–Pt_(2)Os/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–Pt_(2)Os/C.
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| Additional Information: | © 2014 Elsevier B.V. Received 6 August 2013; Received in revised form 20 November 2013; Accepted 3 January 2014; Available online 10 January 2014. The financial supports from the National Science Council of Taiwan (NSC-100-2221-E009-075-MY3, NSC 101-3113-P-008- 001) and National Science Foundation (CBET-1067848, Caltech) are gratefully acknowledged. | |||||||||
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| Subject Keywords: | Oxygen reduction reaction; Platinum; Osmium; Dealloying process; Quantum mechanics | |||||||||
| Record Number: | CaltechAUTHORS:20140421-104729502 | |||||||||
| Persistent URL: | http://resolver.caltech.edu/CaltechAUTHORS:20140421-104729502 | |||||||||
| Official Citation: | Lee, Y.-J., Hsieh, Y.-C., Tsai, H.-C., Lu, I. T., Wu, Y.-H., Yu, T. H., . . . Wu, P.-W. (2014). Dealloyed Pt2Os nanoparticles for enhanced oxygen reduction reaction in acidic electrolytes. Applied Catalysis B: Environmental, 150–151(0), 636-646. doi: http://dx.doi.org/10.1016/j.apcatb.2014.01.004 | |||||||||
| Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||
| ID Code: | 45070 | |||||||||
| Collection: | CaltechAUTHORS | |||||||||
| Deposited By: | Jason Perez | |||||||||
| Deposited On: | 22 Apr 2014 22:15 | |||||||||
| Last Modified: | 21 Nov 2016 21:09 |
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