Fig. 1: Morphological and structural characterization of PW-Co3N NWA/NF.

a Schematic illustration of the formation process; b–d FESEM and e TEM images; f HRTEM analysis; g HAADF-STEM image and corresponding elemental mapping results; h aberration corrected HAADF-STEM image; i the enlarged picture from (h); j atomically resolved HAADF-STEM image; k the corresponding FFT image of (h).