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Activation of Methanol-Tolerant Carbon-Supported RuSex Electrocatalytic Nanoparticles Towards More Efficient Oxygen Reduction
|Krzysztof Miecznikowski 1, Paweł J. Kulesza 1, Aneta Kolary-Żurowska 1, Agata Zieleniak 1, Adam Lewera 1, Beata Baranowska 1, Sebastian M. Fiechter 2, Peter Bogdanoff 2, Iris Dorbandt 2, Roberto Marassi 3|
1. Warsaw University, Faculty of Chemistry, Pasteura 1, Warszawa 02-093, Poland
Although platinum based electrocatalysts are still the most commonly used systems for the reduction of oxygen in acid media, there have been many attempts to synthesize different catalytic materials. Bi-component ruthenium-selenium (RuSex) nanoparticles can be viewed as a promising alternative to Pt and Pt-alloy based cathode materials.
In our recent preliminary communication , we have reported that modification of carbon-supported RuSex nanoparticles with ultra-thin films of tungsten oxide tends to shift the oxygen reduction potential towards more positive values. An electrocatalytic system, that utilizes tungsten oxide modified carbon-supported RuSex nanoparticles, is developed and characterized here using transmission electron microscopy and such electrochemical diagnostic techniques as cyclic volammetry and rotating ring-disk voltammetry and upon introduction (as cathode) to the low-temperature hydrogen-oxygen fuel cell. Following modification of RuSex catalytic centers with ultra-thin films of WO3, the potential of oxygen reduction in 0.5 mol dm-3 H2SO4 (in the absence and presence of methanol) is shifted ca. 80 mV (under rotating disk voltammetric conditions) towards more positive values, and the percent formation (at ring) of the undesirable hydrogen peroxide has decreased approximately twice when compared to the WO3-free system. Further, the WO3-modified RuSex (carbon-free) samples have been immobilized on the gold electrode surface for Synchrotron X-ray Photoelectron Spectroscopy (XPS) examination. Relative to bare electrocatalyst, an increase of power density over 10 mW cm-2 (to 100 mW cm-2 at 80oC with 300 mA cm-2) has been observed upon deposition of WO3-modified RuSex.
 D. Cao, A. Wieckowski, J. Inukai, N. Alonso-Vante, J.Electrochem. Soc., 153 (2006) A869. P. J. Kulesza, K. Miecznikowski, B. Baranowska, M. Skutnik, S. Fiechter, P. Bogdanoff, I. Dorbandt, Electrochem. Comm., 8 (2006) 904.
Presentation: Oral at E-MRS Fall Meeting 2007, Symposium D, by Krzysztof Miecznikowski
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-06-15 13:03 Revised: 2009-06-07 00:44