Ordered Iron- and Nitrogen-Doped Carbon Framework as a Carbon Monoxide-Tolerant Alkaline Anion-Exchange Membrane Fuel Cell Catalyst

摘要

In this work, we have successfully developed a series of ordered Fe- and N-doped carbon (Fe-N-C) catalysts for alkaline anion-exchange membrane fuel cells (AEMFCs) using ordered SiO2 nanospheres as a scaffold template. Compared to the previous work, the SiO2 nanosphere templates used in this work are more well-ordered and size-controlled, which increases the surface area of the Fe-N-C framework material. We observed that the 30nm@Fe-N-C sample exhibits orderly arranged mesopores, interconnected conductive networks, and large surface area (1192m(2)g(-1)). Moreover, the 30nm@Fe-N-C sample shows significantly enhanced oxygen reduction reaction (ORR) activity compared to commercial Pt/C. A more-positive half-wave potential of 0.84V (vs. reversible hydrogen electrode, RHE) and remarkably stable limiting current of approximate to 6.1mAcm(-2) is demonstrated by a three-electrode configuration rotating disk electrode (RDE) system in 0.1m KOH solution. An AEMFC based on the 30nm@Fe-N-C sample showed a maximum power density of 100mWm(-2) at a high current density of 230mAcm(-2). In addition, we found the AEMFC based on 30nm@Fe-N-C catalyst could steadily operate for more than 60h with only 4.65% performance degradation under constant voltage conditions (0.6V). More interestingly, this catalyst shows an excellent tolerance for CO as well as remarkably long-term stability with more than 89.9% retention of its initial activity after 41.6min operation, which is obviously superior to the commercial Pt/C catalyst (59% initial activity retention).