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Title: Oxygen Reduction Kinetics on Pt Monolayer Shell Highly Affected by the Structure of Bimetallic AuNi Cores

Authors:
; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1354474
Report Number(s):
BNL-112991-2016-JA
Journal ID: ISSN 0897-4756
DOE Contract Number:
SC00112704
Resource Type:
Journal Article
Resource Relation:
Journal Name: Chemistry of Materials; Journal Volume: 28; Journal Issue: 15
Country of Publication:
United States
Language:
English

Citation Formats

Chen, Guangyu, Kuttiyiel, Kurian A., Su, Dong, Li, Meng, Wang, Chiu-Hui, Buceta, David, Du, Chunyu, Gao, Yunzhi, Yin, Geping, Sasaki, Kotaro, Vukmirovic, Miomir B., and Adzic, Radoslav R.. Oxygen Reduction Kinetics on Pt Monolayer Shell Highly Affected by the Structure of Bimetallic AuNi Cores. United States: N. p., 2016. Web. doi:10.1021/acs.chemmater.6b00500.
Chen, Guangyu, Kuttiyiel, Kurian A., Su, Dong, Li, Meng, Wang, Chiu-Hui, Buceta, David, Du, Chunyu, Gao, Yunzhi, Yin, Geping, Sasaki, Kotaro, Vukmirovic, Miomir B., & Adzic, Radoslav R.. Oxygen Reduction Kinetics on Pt Monolayer Shell Highly Affected by the Structure of Bimetallic AuNi Cores. United States. doi:10.1021/acs.chemmater.6b00500.
Chen, Guangyu, Kuttiyiel, Kurian A., Su, Dong, Li, Meng, Wang, Chiu-Hui, Buceta, David, Du, Chunyu, Gao, Yunzhi, Yin, Geping, Sasaki, Kotaro, Vukmirovic, Miomir B., and Adzic, Radoslav R.. 2016. "Oxygen Reduction Kinetics on Pt Monolayer Shell Highly Affected by the Structure of Bimetallic AuNi Cores". United States. doi:10.1021/acs.chemmater.6b00500.
@article{osti_1354474,
title = {Oxygen Reduction Kinetics on Pt Monolayer Shell Highly Affected by the Structure of Bimetallic AuNi Cores},
author = {Chen, Guangyu and Kuttiyiel, Kurian A. and Su, Dong and Li, Meng and Wang, Chiu-Hui and Buceta, David and Du, Chunyu and Gao, Yunzhi and Yin, Geping and Sasaki, Kotaro and Vukmirovic, Miomir B. and Adzic, Radoslav R.},
abstractNote = {},
doi = {10.1021/acs.chemmater.6b00500},
journal = {Chemistry of Materials},
number = 15,
volume = 28,
place = {United States},
year = 2016,
month = 8
}
  • Here, we describe pronounced effects of structural changes of the AuNi cores on the oxygen reduction reaction (ORR) activity of a Pt monolayer shell. The study of alloyed AuNi nanoparticles compared with AuNi core–shell structured nanoparticles revealed configurations having different electronic and electrochemical properties. Controlled alloying of Au with Ni was essential to tune the electronic properties of Au interacting with the Pt monolayer shell to achieve suitable adsorption of O 2 on Pt for expediting the ORR. The alloyed AuNi nanoparticles made the Pt shell more catalytically active for the ORR than the core–shell structured AuNi nanoparticles. The Ptmore » monolayer supported on the alloyed AuNi nanoparticles showed the Pt mass and specific activities as high as 1.52 A mg –1 and 1.18 mA cm –2, respectively, with almost no loss over 5 000 cycles of stability test. This high ORR activity is ascribed to the role of nonspecific steric configuration of Ni atoms changing the electronic properties of the alloy that affect the oxygen and water interaction with the Pt shell and facilitate increased ORR kinetics.« less
  • Here, platinum monolayer electrocatalyst are known to exhibit excellent oxygen reduction reaction (ORR) activity depending on the type of substrate used. Here we demonstrate a relationship between the ORR electrocatalytic activity and the surface electronic structure of Pt monolayer shell induced by various IrM bimetallic cores (M=Fe, Co, Ni or Cu). The relationship is rationalized by comparing density functional theory calculations and experimental results. For an efficient Pt monolayer electrocatalyst, the core should induce sufficient contraction to the Pt shell leading to a downshift of the d-band center with respect to the Fermi level. Depending on the structure of themore » IrM, relative to that of pure Ir, this interaction not only alters the electronic and geometric structure but also induces segregation effects. Combined these effects significantly enhance the ORR activities of the Pt monolayer shell on bimetallic Ir cores electrocatalysts.« less
  • We synthesized a low-Pt content electrocatalyst consisting of a Pt monolayer placed on carbon-supported thermally treated IrNi core-shell structured nanoparticles using galvanic displacement of a Cu monolayer deposited at underpotentials. The Pt mass activity of the Pt{sub ML}/IrNi/C electrocatalyst obtained in a scale-up synthesis is approximately 3 times higher than that of the commercial Pt/C electrocatalyst. The electronic and geometrical effects of the IrNi substrate on the Pt monolayer result in its higher catalytic activity than that of Pt nanoparticles. The structure and composition of the core-shell nanoparticles were verified using transmission electron microscopy and in situ X-ray absorption spectroscopy,more » while a potential cycling test was employed to confirm the stability of the electrocatalyst. Our experimental results, supported by the density functional calculations using a sphere-like model, demonstrate an effective way of using Pt that can resolve key problems of cathodic oxygen reduction hampering fuel cell commercialization.« less