Fig. 2: Characterizations of AC-Ir NSs.

a TEM image, (b) AFM image, (c) EDS elemental mapping images and (d) HRTEM image of AC-Ir NSs. e1, f1, g1 FFT patterns, (e2, f2, g2) IFFT images of amorphous domain, crystalline domain and amorphous–crystalline phase boundary, respectively. h Aberration-corrected HAADF-STEM image around amorphous–crystalline phase boundary (inset: dark cyan: amorphous domain, dark green: crystalline domain.). i EELS spectroscopy of amorphous domain and crystalline domain corresponding to the selected area in (h), respectively. Note: AC-Ir NSs were obtained at annealing temperature of 300 oC.