( 武汉理工大学 材料复合新技术国家重点实验室，
武汉 430070)
摘 要: 用铁作掺杂元素， 通过液相均相沉淀-气/固高温还原两段反应方法制备了碳载Pt-Fe合金催化剂， 比较了3种不同Fe含量催化剂的电催化性能。 采用X射线衍射和X光电子能谱技术研究了Fe掺杂对Pt/C催化剂晶体结构及表面元素存在形态的影响。 结果显示： Pt-Fe/C催化剂比单一Pt/C催化剂有更小的晶格参数， 其中Fe元素可能的存在形态应为与铂结合的合金态， 但不排除表面存在部分氧化态。单电池放电稳定性实验表明： 在200mA·cm-2电流密度下放电时电池电压基本稳定， 其中Pt与Fe摩尔比为1∶1时电极催化效果相应较好， 但大电流密度放电时电池电压下降比单一Pt/C催化剂电极的快， 这说明Fe的加入能提高催化剂的电催化性能， 但阴极表面氧原子浓度较大时， Fe可能发生氧化而使得电极稳定性受到影响。
关键字: 质子交换膜； 燃料电池； Pt-Fe/C催化剂； 两步反应法； 电化学催化
Pt /C catalyst for proton exchange membrane fuel cell
（ State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,
Wuhan University of Technology, Wuhan 430070, China）
Abstract: Carbon-supported Pt-Fe alloy catalysts were prepared by two-step reaction containing liquid depositing and gas-solid reducing. The electrocatalytic characteristics of the catalysts with different contents of Fe were compared. The effects of Fe on the crystal structure and the state of elements in Pt-Fe/C were investigated by XRD and XPS techniques. The results show that Pt-Fe/C catalyst has smaller crystal lattice parameter than Pt/C catalyst and the potential state of Fe in it should be alloy state integrated with Pt, but a portion of Fe in the catalyst surface exists as ferric oxides as well. It is also found that the catalyst in which molar ratio of Pt to Fe is 1∶1 is provided with preferable catalytic characteristic, but the electrode stability is not much satisfied when single cell using Pt-Fe/C as cathode is discharged at larger current density.
Key words: proton exchange membrane; fuel cell; Pt-Fe/C catalyst; two-step reaction; electrochemical catalysis
