Preparation of ternary Pt/Rh/SnO2 anode catalysts for use in direct ethanol fuel cells and their electrocatalytic activity for ethanol oxidation reaction

• Ternary Pt/Rh/SnO2 catalysts can be prepared by the modified Bönnemann method.
• Pt and Rh components were metallic and Sn component was oxidized to SnO2.
• Each Pt/Rh/SnO2/CB catalyst was composed of Pt, Rh and/or SnO2 nanoparticles.
• EOR activity of Pt-65/Rh-10/SnO2/CB is higher than that of Pt/SnO2/CB.
• EOR at 0.6 V for Pt/Rh/SnO2/CB decayed more slowly than that at the Pt/SnO2/CB.

Pt, Rh and SnO2 nanoparticle-loaded carbon black (Pt/Rh/SnO2/CB) catalysts with different contents of Pt and Rh were prepared by the modified Bönnemann method. The mean size and size distribution of Pt, Rh and SnO2 for Pt-71/Rh-4/SnO2/CB (Pt : Rh : Sn = 71 at.%: 4 at.%: 25 at.%) were 3.8 ± 0.7, 3.2 ± 0.7 and 2.6 ± 0.5 nm, respectively, indicating that Pt, Rh and SnO2 were all nanoparticles. The onset potential of ethanol oxidation current for the Pt-65/Rh-10/SnO2/CB and Pt-56/Rh-19/SnO2/CB electrodes was ca. 0.2 V vs. RHE which was ca. 0.2 V less positive than that for the Pt/CB electrode. The oxidation current at 0.6 V for the Pt/Rh/SnO2/CB electrode (ca. 2% h−1) decayed more slowly than that at the Pt/SnO2/CB electrode (ca. 5% h−1), indicating that the former was superior in durability to the latter. The main product of EOR in potentiostatic electrolysis at 0.6 V for the Pt-71/Rh-4/SnO2/CB electrode was acetic acid.