Fig. 4: Morphology evolution of AE-ZIF after electrocatalysis.

a, d TEM images of single-particle AE-ZIF before (a) and after 12 h amperometry (d). b, e Schematic diagrams and enlarged TEM images of AE-ZIF edge before (b) and after 12 h amperometry (e), the lower corresponding FFT patterns. c, f Elemental mapping of single-particle AE-ZIF before (c) and after (f) 12 h amperometry showing the Co, O, N and C distribution.