Screening and characterization of bimetallic Pt–M (M = Y, La, Ce, Pr, Nd, Gd) electrocatalysts for the oxygen reduction reaction

In this study bimetallic platinum–metal (Pt–M; M = Y, La, Ce, Pr, Nd, Gd) electrocatalyst arrays were fabricated through a combinational method using a dispensing system. These Pt-based electrocatalyst arrays were then rapidly screened for their suitability for the oxygen reduction reaction (ORR) by...

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Bibliographic Details
Published in:Electrochimica acta 2020-04, Vol.340, p.136012, Article 136012
Main Authors: Weng, Yu-Ching, Wu, Che-Chi, Wang, Hsin-Jen, Wang, Yun-Ya
Format: Article
Language:English
Subjects:
Alloy
Arrays
Bimetals
Cerium
Composition
Electrocatalyst
Electrocatalysts
Electron transfer
Gadolinium
Hydrogen peroxide
Lanthanum
Microscopy
Morphology
Oxygen reduction reaction
Oxygen reduction reactions
Platinum
Praseodymium
Reaction kinetics
Rotating disks
Scanning electrochemical microscopy
Sodium sulfate
Substrates
Sulfuric acid
Yttrium
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Summary:In this study bimetallic platinum–metal (Pt–M; M = Y, La, Ce, Pr, Nd, Gd) electrocatalyst arrays were fabricated through a combinational method using a dispensing system. These Pt-based electrocatalyst arrays were then rapidly screened for their suitability for the oxygen reduction reaction (ORR) by using the tip generation–substrate collection mode of scanning electrochemical microscopy; O2 was generated at the tip and it was reduced at spots of the electrocatalyst on the substrate. Scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffractometry were employed to analyze the surface morphologies, elemental compositions, and crystallinities of the electrocatalysts. Tip/substrate voltammetry, approach curve analysis, and rotating disk electrode analysis were used to examine the kinetics of the potential electrocatalysts for the ORR. Among the prepared electrocatalysts, a spot having the composition Pt7Y3 provided the highest current in 0.01 M H2SO4/0.1 M Na2SO4. The Pt7Y3 electrocatalyst exhibited excellent electrocatalytic activity toward the ORR, with a Tafel slope of 123 mV, a rate constant of 0.023 cm/s, and a transfer coefficient of 0.47. The electron transfer numbers of the binary Pt-based electrocatalysts were all close to 4, indicating that their mechanisms of oxygen reduction followed the four-electron reduction pathway. Furthermore, the percentage of H2O2 produced during the ORR on the Pt7Y3 electrocatalyst was the lowest among these tested systems, with a value of less than 2%.
ISSN:0013-4686
1873-3859
DOI:10.1016/j.electacta.2020.136012