Stabilization of Platinum Oxygen-Reduction Electrocatalysts Using Gold Clusters

Science ◽  
2007 ◽  
Vol 315 (5809) ◽  
pp. 220-222 ◽  
Author(s):  
J. Zhang ◽  
K. Sasaki ◽  
E. Sutter ◽  
R. R. Adzic
Keyword(s):  
Oxygen Reduction ◽  
Pt Nanoparticles ◽  
Reduction Reaction ◽  
Oxidation Potential ◽  
Gold Clusters ◽  
Pt Catalyst ◽  
Potential Cycling ◽  
Au Clusters ◽  
X Ray Absorption

We demonstrated that platinum (Pt) oxygen-reduction fuel-cell electrocatalysts can be stabilized against dissolution under potential cycling regimes (a continuing problem in vehicle applications) by modifying Pt nanoparticles with gold (Au) clusters. This behavior was observed under the oxidizing conditions of the O2 reduction reaction and potential cycling between 0.6 and 1.1 volts in over 30,000 cycles. There were insignificant changes in the activity and surface area of Au-modified Pt over the course of cycling, in contrast to sizable losses observed with the pure Pt catalyst under the same conditions. In situ x-ray absorption near-edge spectroscopy and voltammetry data suggest that the Au clusters confer stability by raising the Pt oxidation potential.

scholarly journals In Situ X-Ray Absorption Spectroscopy Disentangles the Roles of Copper and Silver in a Bimetallic Catalyst for the Oxygen Reduction Reaction

2020 ◽  
Vol 32 (5) ◽  
pp. 1819-1827
Author(s):  
Brenna M. Gibbons ◽  
Melissa Wette ◽  
Michaela Burke Stevens ◽  
Ryan C. Davis ◽  
Samira Siahrostami ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Absorption Spectroscopy ◽  
Bimetallic Catalyst ◽  
Reduction Reaction ◽  
X Ray ◽  
X Ray Absorption

scholarly journals Unveiling the Degradation Nature of Pt/NbOx/C Catalysts for Oxygen Reduction Reaction via in situ X-ray Absorption Spectroscopy

2021 ◽  
Author(s):  
Ershuai Liu ◽  
Qingying Jia ◽  
Jun Yang ◽  
Kai Sun ◽  
Li Jiao ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Absorption Spectroscopy ◽  
Reduction Reaction ◽  
X Ray ◽  
Orr Activity ◽  
X Ray Absorption

Among various metal nanoparticles supported on metal oxide (MMO) catalysts, the Pt/NbOx/C system has promising oxygen reduction reaction (ORR) activity as cathode for proton exchange membrane fuel cells (PEMFCs). Herein, we study a series of Pt/NbOx/C catalysts with tunable structural and electronic properties via physical vapor deposition and unravel the nature of metal and metal oxide interaction (MMOI) by characterizing this system under reactive conditions. By conducting in situ X-ray absorption spectroscopy (XAS) experiments, we demonstrate the Pt preferably interacts with O but not Nb in the Pt/NbOx/C system and such Pt-O interaction benefits the ORR activity via electronic effect rather than strain effect. We also provide clear evidence for the formation of metallic Nb phase at the early stage of PEMFC operation and identify severe particle growth of Pt after long-term PEMFC operation. These findings deepen our understanding of the degradation mechanism of MMO catalysts during long-term PEMFC operation.

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