Trimetallic catalyst based on PtRu modified by irreversible adsorption of Sb for direct ethanol fuel cells

• Trimetallic catalysts were prepared by adsorbing Sb onto PtRu/C.
• Higher ethanol oxidation currents were found for PtRu/C–Sb electrodes.
• FTIR showed that PtRu/C–Sb favours acetic acid as final product.
• Under fuel cell condition, PtRu/C–Sb showed higher power densities than PtRu/C.

In this work, PtRu/C–Sb materials prepared by adding a Sb salt to the ink of commercial PtRu/C were studied as catalysts for ethanol oxidation. The prepared trimetallic catalysts showed enhanced properties for ethanol oxidation through a wide range of surface coverages. However, coverage higher than 0.7 of Sb on PtRu/C causes the decrease of the catalytic activity suggesting that specific sites composed of 3 metals are necessary to achieve the highest performance. In situ Fourier Transform Infrared Spectroscopy experiments were also performed to compare the reaction products of the bimetallic and trimetallic catalysts. The catalysts were also tested under fuel cell conditions. Also in this case, higher power densities, higher open-circuit voltages and better stability than the bimetallic substrate were found. With this catalyst preparation method, the catalysts showed 2 times higher current densities than for the PtRu catalysts and 6 times better than for pure Pt anodes.

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