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Atomistic Explanation of the Dramatically Improved Oxygen Reduction Reaction of Jagged Platinum Nanowires, 50 times better than Pt

Chen, Yalu and Cheng, Tao and Goddard, William A., III (2020) Atomistic Explanation of the Dramatically Improved Oxygen Reduction Reaction of Jagged Platinum Nanowires, 50 times better than Pt. Journal of the American Chemical Society, 142 (19). pp. 8625-8632. ISSN 0002-7863. https://resolver.caltech.edu/CaltechAUTHORS:20200422-125311157

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Abstract

Pt is the best catalyst for the oxygen reduction reactions (ORRs), but it is far too slow. Huang and co-workers showed that dealloying 5 nm Ni7Pt3 nanowires (NW) led to 2 nm pure Pt jagged NW (J-PtNW) with ORRs 50 times faster than Pt/C. They suggested that the undercoordinated surface Pt atoms, mechanical strain, and high electrochemically active surface area (ECSA) are the main contributors. We report here multiscale atomic simulations that further explain this remarkably accelerated ORR activity from an atomistic perspective. We used the ReaxFF reactive force field to convert the 5 nm Ni₇Pt₃ NW to the jagged 2 nm NW. We applied quantum mechanics to find that 14.4% of the surface sites are barrierless for O_(ads) + H₂O_(ads) → 2OH_(ads), the rate-determining step (RDS). The reason is that the concave nature of many surface sites pushes the OH bond of the H₂O_(ads) close to the O_(ads), leading to a dramatically reduced barrier. We used this observation to predict the performance improvement of the J-PtNW relative to Pt (111). Assuming every surface site reacts independently with this predicted rate leads to a 212-fold enhancement at 298.15 K, compared to 50 times experimentally. The atomic structures of the active sites provide insights for designing high-performance electrocatalysts for ORR.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/jacs.9b13218DOIArticle
ORCID:
AuthorORCID
Chen, Yalu0000-0002-0589-845X
Cheng, Tao0000-0003-4830-177X
Goddard, William A., III0000-0003-0097-5716
Additional Information:© 2020 American Chemical Society. Received: December 8, 2019; Published: April 22, 2020. This research was supported by ONR (N00014-18-1-2155). Y.C. was supported by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993. This work uses the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation Grant Number ACI-1053575, and the computational resources of Caltech High Performance Computing Center (HPC). The authors declare no competing financial interest.
Group:JCAP
Funders:
Funding AgencyGrant Number
Office of Naval Research (ONR)N00014-18-1-2155
Joint Center for Artificial Photosynthesis (JCAP)UNSPECIFIED
Department of Energy (DOE)DE-SC0004993
NSFACI-1053575
Other Numbering System:
Other Numbering System NameOther Numbering System ID
WAG1378
Issue or Number:19
Record Number:CaltechAUTHORS:20200422-125311157
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200422-125311157
Official Citation:Atomistic Explanation of the Dramatically Improved Oxygen Reduction Reaction of Jagged Platinum Nanowires, 50 Times Better than Pt. Yalu Chen, Tao Cheng, and William A. Goddard III. Journal of the American Chemical Society 2020 142 (19), 8625-8632; DOI: 10.1021/jacs.9b13218
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:102719
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:22 Apr 2020 20:00
Last Modified:11 Jul 2020 09:55

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