The effect of oxygen containing species on the catalytic activity of ethanol oxidation for PtRuSn/C catalysts

The effect of oxygen containing species (OCS) on the electrochemical activities of carbon supported PtRu, PtSn, and PtRuSn electrocatalysts has been investigated. The catalysts are prepared by the precipitation–deposition method and applied for the ethanol oxidation reaction (EOR). The oxidation treatment is applied to generate the OCS for these catalysts in order to realize their influences on the mechanism of EOR. The distinct effects of OCS on EOR performance are observed. RuO2 enhances the activity of EOR only in high potential region due to the promotion of CO oxidation, while Pt3Sn, SnO or SnO2 can promote both dissociative adsorption of ethanol on Pt surface and the CO oxidation reaction, thus the EOR activity increases in whole potential region. However, for the oxidized ternary PtRuSn catalysts where RuO2 and SnO2 coexist and cover the Pt active sites, the EOR activity deteriorates. Herein, the best catalyst for EOR is the as-reduced PtRuSn/C among all samples owing to the surface OCS (SnO) and an appropriate Ru/Sn surface ratio. For the oxidized sample, PtRu/C displays high EOR activity. Models for the mechanism of EOR on the PtRuSn/C catalysts are also proposed on the basis of the results presented here.