Displacement triangular Ag/Pd nanoplate as methanol- tolerant electrocatalyst in oxygen reduction reaction

Porous triangular Ag/Pd nanoplates with different alloy ratios, including Ag18Pd1, Ag18Pd1.5, and Ag18Pd2, were successfully prepared by a galvanic displacement reaction. These alloy nanoplates were then used as methanol-tolerant electrocatalysts in an alkaline oxygen reduction reaction (ORR). Electrochemical measurements were conducted using an ultrathin film rotating ring-disk electrode. The mass activity was found to decrease in the order Ag18Pd1 > Ag18Pd2 > Ag18Pd1.5 > Pt nanoparticles > Pd nanoparticles, similar to an observation made in a past analysis of the nanoplates in an electrolyte of free methanol; this indicates that these nanoplate catalysts are more economical than Pd nanoparticles, and even Pt nanoparticles. Additionally, compared to the reactive direction in the case of Pt and Pd nanoparticles toward methanol oxidation in an ORR electrolyte with methanol, all Ag/Pd nanoplate catalysts experienced cathodic currents, which indicate that ORRs occurred even in the presence of methanol. Despite working in a methanol-tolerant solution, the prepared alloy nanoplates still exhibited high electroactivity.

► Porous triangular Ag/Pd nanoplates with different alloy ratios have been successfully prepared by a galvanic displacement reaction. ► As determined via XRD and EDX measurements, the nanosponges feature fcc and mixed-alloy structures. ► These alloy nanoplates were then successfully used as a methanol-tolerant electrocatalyst in an alkaline oxygen reduction reaction. ► The specific and mass activities of these nanoplate catalyst, Pt nanoparticles, and Pd nanoparticles were compared.