What is it about?
We have prepared and characterized a SnO2-decorated Pt-Sn(oxidized)/C cathode catalyst in a polymer electrolyte fuel cell (PEFC). The unique increase in the ORR performance of the Pt-Sn(oxidized)/C was ascribed to a promoting effect of SnO2 nano-islands formed on the surface of Pt¬3Sn core nanoparticles. In-situ X-ray absorption near-edge structure (XANES) analysis at Pt LIII-edge in increasing/decreasing potential operations and at Sn K-edge in the I-V load cycles revealed a remarkable suppression of Pt oxidation compared with the Pt/C at higher potentials and no change in the Sn oxidation state, respectively, resulting in the higher performance and stability of the Pt-Sn(oxidized)/C catalyst due to the SnO2 nano-islands under the PEFC operation conditions.
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Why is it important?
A new SnO2 nano-islands-decorated Pt-Sn(oxidized)/C cathode catalyst with a higher ORR activity than a commercial Pt/C was fabricated and characterized by in situ XAFS, STEM, XPS, and electrochemical performances. The SnO2 nano-islands-decorated Pt-Sn(oxidized)/C catalyst suppressed strong oxygen adsorption remarkably compared with the Pt/C, while facilitating the ORR process. As the result, a unique increase in the ORR performance of the Pt-Sn(oxidized)/C was designed.
Perspectives
The SnO2-islands shell on Pt nanoparticle surfaces prevents the Pt cathode surface layers from being over-oxidized and modifies the ORR property of Pt cathode surfaces by electronic and ensemble effects, d-band shift, weakening Pt-O bond, etc., resulting in increasing performance and durability of Pt cathode catalysts in PEFC MEA. The SnO2 nano-islands shell decorated on Pt cores is expected to provide a synergetic effect on the ORR due to efficient and strong interaction between the Pt core and SnO2 nano-islands. In this study, we report the preparation, property and characterization of a SnO2-decorated Pt-Sn(oxidized)/C catalyst as a promising MEA cathode for the ORR in PEFC.
Yasuhiro Iwasawa
The University of Electro-Communications
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This page is a summary of: Performance and characterization of a Pt–Sn(oxidized)/C cathode catalyst with a SnO2-decorated Pt3Sn nanostructure for oxygen reduction reaction in a polymer electrolyte fuel cell, Physical Chemistry Chemical Physics, January 2013, Royal Society of Chemistry,
DOI: 10.1039/c3cp52323c.
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