聚苯胺衍生Fe-N-C催化剂在碱性电解质中对氧还原反应的催化性能

经过热解聚苯胺、碳和FeCl₃的混合物制备的Fe-N-C材料在酸性电解质中对氧还原反应表现出高的催化活性;由于材料中不存在任何贵金属, 因而被认为是一类新型非贵金属氧还原催化剂. 然而这类催化剂在碱性电解质中催化氧还原反应的性能如何尚不清楚. 本文使用旋转圆盘电极技术考察了制备的两个Fe-N-C催化剂在KOH水溶液中催化氧还原反应性能, 发现这两个催化剂表现出比无金属的N掺杂碳材料更高的活性. 与商业Pt/C催化剂相比, 它们催化氧还原反应的起始电势和半波电势分别仅低60和40 mV左右, 计时电流测试表明, 它们比Pt/C催化剂显示出更好的稳定性. 此外, 在这两个Fe-N-C催化剂上的氧还原反应主要遵循四电子途径. 本工作显示, Fe-N-C材料有望用于碱性燃料电池氧还原反应催化剂.

Performance of polyaniline-derived Fe-N-C catalysts for oxygen reduction reaction in alkaline electrolyte

Without the presence of any precious metal, Fe-N-C materials derived from pyrolysis of polyaniline (PANI)/carbon/FeCl₃ mixtures are recognized as new catalysts for cathodic oxygen reduction reaction (ORR) in acidic electrolyte. How these Fe-N-C catalysts would perform in an alkaline electrolyte remains yet unknown. Reported here are assessments of the ORR performance of two Fe-N-C catalysts (Fe content: 3.4% and 5.9%) in auqeous KOH by rotating disk electrode methods. Both Fe-N-C catalysts were found much more active than those metal-free N-doped carbon materials in literature. Moreover, the ORR onset and half-wave potentials over both Fe-N-C catalysts were respectively within 60 and 40 mV from those delivered by conventional Pt/C catalyst and both Fe-N-C catalysts even showed much superior catalytic stability in chronoamperometric measurement. ORR on the present Fe-N-C catalysts proceeded predominantly via a four-electron transfer mechanism. This work would shed a light on Fe-N-C materials for ORR catalysis in alkaline fuel cells.