Preparation of Pt/Au/Fe₃O₄ nanocomposites and their electrocatalytic activities in methanol oxidation

Pt/Au/Fe₃O₄ nanocomposites were prepared by the continuous reduction method, through loading Pt and Au on the surface of nano Fe₃O₄. The Pt/Au/Fe₃O₄ nanocomposites were characterized by UV-vis spectra, transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectrometer (XPS); their electrocatalytic activities in methanol oxidation were investigated. The results indicated that Au and Pt are uniformly deposited on Fe₃O₄ surface. The cyclic voltammograms of Pt/Au/Fe₃O₄ suggests that the best catalytic performance is achieved when the amount of H₂PtCl₆ added is 8 mL. Current peak i_p is proportional to the square root of scanning speed (v^1/2) and the catalytic methanol oxidation process is under the control of diffusion. The Pt/Au/Fe₃O₄ nanocomposites remain high active during the measurements of cyclic voltammograms for 201 times, suggesting that Pt/Au/Fe₃O₄ is a kind of anode catalyst materials with high chemical activity and stability.