Abstract:
Platinum-silver alloy nanoparticles (Pt
xAg
y NPs) were synthesized in a molten salt system without using any organic surfactants or solvents; the catalytic role of Ag in the methanol electrooxidation reaction (MOR) in alkaline electrolyte over Pt
xAg
y NPs was investigated. The TEM images suggest that Pt
52Ag
48 nanotubes (NTs) can be obtained when the Pt/Ag ratio in the molten salt precursor reaches 1. The methanol electrooxidation reaction test results indicate that the Pt
52Ag
48 NTs with a clean surface exhibits a much better catalytic performance than the conventional Pt black in MOR. Meanwhile, the catalytic activity of the Pt
52Ag
48 NTs is greatly related to the positive potential limit; the peak current of MOR reaches 1.61 mA/μg
Pt with a positive potential limit from -1.0 to 0.5 V (vs. SCE), which is 1.92 times higher than that with a positive potential limit from -1.0 to 0.1 V (vs. SCE). The Ag element in the surface layer of Pt
xAg
y alloy may promote the MOR through a redox process during the electrochemical cycle. The insight shown in work should be beneficial to the application of Pt
xAg
y alloy in the direct methanol fuel cells (DMFCs).