•PdAg and PdAu nanoparticle catalysts were prepared by a wet method without no purification.•PdAg/CB had lower onset potential of glycerol oxidation than Pd/CB due to electronic effect.•PdAg/CB exhibited higher durability for lower potentials than Pd/CB.•PdAu/CB had higher glycerol oxidation current than Pd/CB due to bi-functional effect.•PdAu/CB exhibited higher durability for higher potentials than Pd/CB and PdAg/CB.PdAg and PdAu alloy nanoparticle catalysts for the glycerol oxidation reaction (GOR) were prepared at room temperature by a wet method. The molar ratio of the precursors controlled the bulk composition of the PdAg and PdAu alloys, and their surface composition was Ag-enriched and Pd-enriched, respectively. On PdAg-loaded carbon black (PdAg/CB) electrodes, the onset potential of GOR was 0.10–0.15 V more negative than on the Pd/CB electrode due to the electronic effect. The ratio of GOR peak current densities in the backward and forward sweeps of CVs (ib/if) was smaller because of the improved tolerance to the poisoning species. The ratio of the GOR current density at 60 and 5 min (i60/i5) for the PdAg/CB electrodes was higher for more negative potentials than the Pd/CB electrode. In contrast, the PdAu-loaded CB (PdAu/CB) electrodes had an onset potential of GOR similar to the Pd/CB electrode and a higher GOR peak current density owing to the bi-functional effect. However, the ib/if ratio was higher for PdAu/CB because of the increase in ib as the Pd surface was recovered, and the i60/i5 ratio was higher for more positive potentials, similar to the Pd/CB electrode.

•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.

Highly dispersed Pt and SnO2 double nanoparticles containing different Pt/Sn ratios (denoted as Pt/SnO2/CB) were prepared on carbon black (CB) by the modified Bönnemann method. The average size of Pt and SnO2 nanoparticles was 3.1 ± 0.5 nm and 2.5 ± 0.3 nm, respectively, in Pt/SnO2(3:1)/CB, 3.0 ± 0.5 nm and 2.6 ± 0.3 nm, respectively, in Pt/SnO2(1:1)/CB, and 2.8 ± 0.5 nm and 2.5 ± 0.3 nm, respectively, in Pt/SnO2(1:3)/CB. The Pt/SnO2(3:1)/CB electrode showed the highest specific activity and lowest overpotential for ethanol oxidation reaction (EOR), and was superior to a Pt/CB electrode. Current density for EOR at 0.40 and 0.60 V vs. reversible hydrogen electrode for the Pt/SnO2(3:1)/CB electrode decayed more slowly than that for the Pt/CB electrode because of a synergistic effect between Pt and SnO2 nanoparticles. The predominant reaction product was acetic acid, and its current efficiency was about 70%, while that for CO2 production was about 30%.