Enhancing ethanol oxidation rate at PtRu electro-catalysts using metal-oxide additives

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• 作者：S.C. Zignani ; V. Baglio ; ^{baglio@itae.cnr.it" class="auth_mail" title="E-mail the corresponding author} ; D. Sebastiá ; n ; S. Siracusano ; A.S. Aricò
• 关键词：Direct ethanol fuel cells ; metal-oxide promoters ; PtRu/C catalyst ; ethanol electro-oxidation
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：10 February 2016
• 年：2016
• 卷：191
• 期：Complete
• 页码：183-191
• 全文大小：1976 K

文摘

Metal oxides are investigated, as additives of a PtRu/C catalyst, for enhancing the electro-oxidation of ethanol in acidic solution. High surface area TiO₂ and SnO₂ additives are synthesized and physico-chemically characterized. These oxides are added to PtRu/C during the catalytic ink preparation to obtain tri-metallic composite electrodes. These composite electro-catalysts are investigated for the ethanol electro-oxidation in half-cell configuration in comparison with additive-free PtRu/C and Pt/C catalysts. The PtRu-based composite catalyst containing SnO₂ promoter shows a lower onset potential and larger current density for ethanol oxidation than the additive-free catalyst and that containing TiO₂ promoter. The composite catalysts (PtRu/C + metal oxide) are also used in a direct ethanol fuel cell under practical operating conditions and assessed against the benchmark PtRu catalyst. An increase in performance is recorded with the composite tri-metallic electrodes. The analysis of electro-catalytic activity towards ethanol oxidation reaction and ethanolic residues coverage indicates an enhanced capability to activate ethanol chemisorption or a larger electroactive surface area, together with a faster intrinsic activity at lower overpotential, as the reasons for the improved performance with the use of metal oxide additives.