Fig. 2From: Highly Active and Stable Fe-N-C Oxygen Reduction Electrocatalysts Derived from Electrospinning and In Situ PyrolysisSEM images of FN-800: before calcination (a), calcination in 800 °C (b), and with acid immerse (c). TEM images of FN-800: calcination in 800 °C (d); with acid immerse (e, f). The inset of f is HERTEM of the white circle area. SEM and corresponding element mapping image of FN-800 (g SEM; i C; ii N; iii Fe)Back to article page