Effect of the relationship between particle size, inter-particle distance, and metal loading of carbon supported fuel cell catalysts on their catalytic activity

Author(s)

Corradini, Patricia Gon ^[1] ; Pires, Felipe I. ^[1] ; Paganin, Valdecir A. ^[1] ; Perez, Joelma ^[1] ; Antolini, Ermete ^[2]

Affiliation

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[2] Scuola Sci Mat, I-16016 Genoa - Italy

• Document type: Journal article
• Source: JOURNAL OF NANOPARTICLE RESEARCH; v. 14, n. 9 SEP 2012.
• Web of Science Citations: 14

Abstract

The effect of the relationship between particle size (d), inter-particle distance (x(i)), and metal loading (y) of carbon supported fuel cell Pt or PtRu catalysts on their catalytic activity, based on the optimum d (2.5-3 nm) and x(i)/d (>5) values, was evaluated. It was found that for y < 30 wt%, the optimum values of both d and x(i)/d can be always obtained. For y >= 30 wt%, instead, the positive effect of a thinner catalyst layer of the fuel cell electrode than that using catalysts with y < 30 wt% is concomitant to a decrease of the effective catalyst surface area due to an increase of d and/or a decrease of x(i)/d compared to their optimum values, with in turns gives rise to a decrease in the catalytic activity. The effect of the x(i)/d ratio has been successfully verified by experimental results on ethanol oxidation on PtRu/C catalysts with same particle size and same degree of alloying but different metal loading. Tests in direct ethanol fuel cells showed that, compared to 20 wt% PtRu/C, the negative effect of the lower x(i)/d on the catalytic activity of 30 and 40 wt% PtRu/C catalysts was superior to the positive effect of the thinner catalyst layer. (AU)

• FAPESP's process: 10/20045-0 - Fuel cells: contributions to the development of catalysts and to the understanding of scaling up problems
• Grantee: Joelma Perez
• Support Opportunities: Regular Research Grants