关键词: 催化剂, 铂铁合金, 结构有序, 氧还原反应

Abstract:

To improve oxygen reduction reaction catalytic activity of the precious metals platinum for fuel cell, the precursors of carbon-supported structurally disordered platinum-iron alloy (D-Pt₃Fe/C and D-PtFe/C) catalysts with different compositions were synthesized via a modified polyol reduction method. Then, by optimizing the annealing conditions in the inert gas, we turned the structurally disordered platinum-iron alloy to the structurally ordered platinum-iron alloy (O-Pt₃Fe/C and O-PtFe/C) catalysts. The structural characterizations of the as-prepared catalysts were performed by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and X-ray photoelectron spectroscopy (XPS). The results showed that the as-prepared structurally ordered platinum-iron alloy nanoparticles with a small size in edge length of 4 ~ 6 nm were highly dispersed on the carbon support. The electrocatalytic performances of the as-prepared catalysts were evaluated by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). It was found that the catalytic activity of O-PtFe/C was enhanced as compared to that of O-Pt₃Fe/C. The mass activity and specific activity of O-PtFe/C are 271.54 mA•g^-1_Ptand 0.73 mA•cm^-2_Pt, respectively, which are 4.3 and 7.3 times higher than those of commercial JM Pt/C catalyst. The catalytic activities of both the as-prepared structurally ordered platinum-iron alloy catalysts for oxygen reduction reaction were higher than that of JM Pt/C catalyst.

Key words: catalysts, platinum-iron alloy, structurally ordered, oxygen reduction reaction