US EPA

4040051 

Journal Article 

Effect of redox state of PtRu electrocatalysts on methanol oxidation activity 

Sirk, AHC; Hill, JM; Kung, SKY; Birss, VI 

2004 

Yes 

Journal of Physical Chemistry B
ISSN: 1520-6106
EISSN: 1520-5207 

108 

2 

689-695 

10.1021/jp036602x 

WOS:000187951700026 

PtRu is a promising catalyst for methanol oxidation in direct methanol fuel cells. However, the most active Pt:Ru ratio and oxidation state of the Ru component are still under investigation. PtRu black was obtained from Johnson Matthey, and the as-received catalyst was treated with either hydrogen or oxygen at elevated temperatures to alter the oxidation state. The samples were characterized by cyclic voltarnmetry (CV), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and X-ray diffraction (XRD) to confirm their redox states and for correlation with their methanol oxidation activity. All of the characterization techniques support successful oxidation and reduction of the PtRu catalyst. The methanol oxidation activity was measured, and the sequence at 25 degreesC was found to be reduced > as-received > oxidized much greater than strongly oxidized. The effect of the drying regime and the dispersing agent for the catalysts was also investigated, and it was found that samples supported using acetic acid were more active than those supported by Nafion, but were less stable and more susceptible to change in catalyst state from heat gun drying.