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Nano Lett. 2018 Apr 11;18(4):2450-2458. doi: 10.1021/acs.nanolett.8b00028. Epub 2018 Mar 29.

Ga-Doped Pt-Ni Octahedral Nanoparticles as a Highly Active and Durable Electrocatalyst for Oxygen Reduction Reaction.

Author information

1
Department of Materials Science and Engineering , Korea Advanced Institute of Science and Technology (KAIST) , 291 Daehak-ro , Yuseong-gu, Daejeon 34141 , Republic of Korea.
2
Materials and Process Simulation Center (MSC) , California Institute of Technology , Pasadena , California 91125 , United States.
3
Pohang Accelerator Laboratory (PAL) and National Institute for Nanomaterials Technology (NINT) , Pohang University of Science and Technology (POSTECH) , Pohang 790-784 , Republic of Korea.
4
Graduate School of Energy, Environment, Water and Sustainability (EEWS) , Korea Advanced Institute of Science and Technology (KAIST) , 291 Daehak-Ro , Yuseong-Gu, Daejeon 34141 , Republic of Korea.
5
Department of Chemistry , Korea Advanced Institute of Science and Technology (KAIST) , 291 Daehak-Ro , Yuseong-Gu, Daejeon , 34141 , Republic of Korea.

Abstract

Bimetallic PtNi nanoparticles have been considered as a promising electrocatalyst for oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells (PEMFCs) owing to their high catalytic activity. However, under typical fuel cell operating conditions, Ni atoms easily dissolve into the electrolyte, resulting in degradation of the catalyst and the membrane-electrode assembly (MEA). Here, we report gallium-doped PtNi octahedral nanoparticles on a carbon support (Ga-PtNi/C). The Ga-PtNi/C shows high ORR activity, marking an 11.7-fold improvement in the mass activity (1.24 A mgPt-1) and a 17.3-fold improvement in the specific activity (2.53 mA cm-2) compared to the commercial Pt/C (0.106 A mgPt-1 and 0.146 mA cm-2). Density functional theory calculations demonstrate that addition of Ga to octahedral PtNi can cause an increase in the oxygen intermediate binding energy, leading to the enhanced catalytic activity toward ORR. In a voltage-cycling test, the Ga-PtNi/C exhibits superior stability to PtNi/C and the commercial Pt/C, maintaining the initial Ni concentration and octahedral shape of the nanoparticles. Single cell using the Ga-PtNi/C exhibits higher initial performance and durability than those using the PtNi/C and the commercial Pt/C. The majority of the Ga-PtNi nanoparticles well maintain the octahedral shape without agglomeration after the single cell durability test (30,000 cycles). This work demonstrates that the octahedral Ga-PtNi/C can be utilized as a highly active and durable ORR catalyst in practical fuel cell applications.

KEYWORDS:

Oxygen reduction reaction (ORR); PtNi octahedral; gallium (Ga); membrane-electrode assembly (MEA); polymer electrolyte membrane fuel cell (PEMFC)

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