US EPA

738603 

Journal Article 

Surface Structures and Electrochemical Activities of Pt Overlayers on Ir Nanoparticles 

Lee, KS; Yoo, SJ; Ahn, D; Jeon, TY; Choi, KH; Park, IS; Sung, YE 

2011 

1 

Langmuir
ISSN: 0743-7463
EISSN: 1520-5827 

27 

6 

3128-3137 

English 

21284392 

10.1021/la103825s 

https://pubs.acs.org/doi/10.1021/la103825s
Exit
 

Pt overlayers were deposited on carbon-supported Ir nanoparticles with various coverages. Structural and electrochemical characterizations were performed using transmission electron microscopy (TEM), X-ray diffraction, high-resolution powder diffraction (HRPD), X-ray photoelectron spectroscopy (XPS), X-ray absorption near-edge spectroscopy (XANES), cyclic voltammetry (CV), CO stripping voltammetry, and N(2)O reduction. The surface of Ir nanoparticles was covered with Pt overlayers with thickness varying from the submonolayer scale to more than two monolayers. Surface analyses such as CV and CO stripping voltammetry indicated that the Pt overlayers were uniformly deposited on the Ir nanoparticles, and the resultant Pt overlayers exhibited gradual changes in surface characteristics toward the Pt surface as the surface coverage increased. The distinct CO stripping characteristics and the enhanced Pt utilization affected electrocatalytic activities for methanol oxidation. The electrochemical stability of the Pt overlayer was compared with a commercial carbon-supported Pt catalyst by conducting a potential cycling experiment.