RuO2 Nanosheet Modified Pt-Based Catalysts as CO Tolerant PEFC Anode

Wednesday, 8 October 2014: 16:20
Sunrise, 2nd Floor, Galactic Ballroom 7 (Moon Palace Resort)
W. Sugimoto, D. Takimoto, and T. Ohnishi (Shinshu University)
PtRu/C are presently used as the anode catalyst for residential polymer electrolyte fuel cells. Anode catalysts with increased CO tolerance is desired since trace amounts of CO residing in reformates poisons the catalysts. In addition, catalyst degradation due to gradual loss of Ru is known to occur due to start/stop cycles. Thus efforts have been made to develop CO-tolerant electrocatalysts with high durability. The addition of nanostructured oxides has shown some promising results. In an earlier study, the authors showed that the addition of oxide nanosheets to carbon supported Pt-based catalysts can act as co-catalysts for the oxidation of adsorbed CO and enhance the durability [1-3]. Here we have studied catalyst activity and durability of PtxRuy/C catalysts modified with RuO2.1 nanosheets (RuO2.1ns) towards the hydrogen oxidation reaction in the presence of CO.

 RuO2.1ns were derived from layered K0.2RuO2.1.nH2O [4]. Commercially available PtxRuy/C were modified with RuO2.1ns following previously described methods [5,6]. Catalytic activity was measured using rotating disk electrodes in 0.1 M HClO4 (25oC) in pure H2 (j(H2)) or 300 ppm CO/H2 (j(CO/H2)). Chronoamperometry was conducted at 20 mV vs RHE at 400 rpm.

 The composite catalyst RuO2.1ns-Pt/C had the same ECSA and j(H2) value as Pt/C, indicating that RuO2.1ns does not impede H2 diffusion to the Pt surface. The j(CO/H2) value of RuO2.1ns-Pt/C was 18% higher than Pt/C.

The j(CO/H2) value of RuO2.1ns-PtRu/C after 1000 consecutive cycles between 0.05 and 0.4 V vs. RHE (v = 100 mV/s) was compared with Pt2Ru3/C. The initial j(CO/H2) of RuO2.1ns-PtRu/C was similar to PtRu/C and Pt2Ru3/C. After cycling, the j(CO/H2) of RuO2.1ns-PtRu/C was 20% higher than commercial catalysts.

 This work was supported in part by the “Polymer Electrolyte Fuel Cell Program” from the New Energy and Industrial Technology Development Organization (NEDO), Japan.

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[2] T. Saida, W. Sugimoto, Electrochim. Acta, 55, 857 (2010).

[3] T. Saida, N. Ogiwara, Y. Takasu, W. Sugimoto, J. Phys. Chem. C, 114, 13390 (2010).

[4] W. Sugimoto, H. Iwata, Y. Yasunaga, Y. Murakami, Y. Takasu, Angew. Chem. Int. Ed.,42, 4092 (2003).

[5] D. Takimoto, C. Chauvin, W. Sugimoto, Electrochem. Commun, 33, 123 (2013).

[6] C. Chauvin, T. Saida W. Sugimoto, J. Electrochem. Soc., 161, F318 (2014).