合成具有高氧还原反应催化活性的结构有序铂铁合金催化剂

Synthesis of Structurally Ordered Platinum-Iron Catalysts with Enhanced Oxygen Reduction Reaction Activity

为提高燃料电池用贵金属铂催化氧还原反应性能,采用改进的多元醇法制备不同金属比例的碳载铂铁合金催化剂(D-Pt_3Fe/C和D-Pt Fe/C)前驱体.随后通过优化在惰性气体环境中的高温煅烧条件,将结构无序的合金结构转变为结构有序的合金催化剂(O-Pt_3Fe/C和O-Pt Fe/C).利用X射线粉末衍射(XRD)、透射电子显微镜(TEM)、电感耦合等离子体原子发射光谱(ICP-AES)和X射线光电子能谱(XPS)对所制得催化剂进行结构表征.结果发现,所制得催化剂的合金纳米颗粒尺寸分布均一(4~6 nm),且均匀负载于碳载体上.利用循环伏安法(CV)、线性扫描伏安法(LSV)对所制得催化剂进行电化学性能评估.结果表明,O-Pt Fe/C的催化活性高于O-Pt_3Fe/C,其质量活性(271.54 m A·g^(-1)Pt)和比活性(0.73 m A·cm-2Pt)分别是商业JM Pt/C催化剂的4.3倍和7.3倍.两种结构有序铂铁催化剂催化氧还原反应活性均高于商业JM Pt/C催化剂.

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-Pt_3Fe/C and D-Pt Fe/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-Pt_3Fe/C and O-Pt Fe/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-Pt Fe/C was enhanced as compared to that of O-Pt_3Fe/C. The mass activity and specific activity of O-Pt Fe/C are 271.54 m A·g-1 Ptand 0.73 m A·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.