Fig. 2: Structural characterization of the SiO2/FeNSiC sample.

a, b Images of TEM observation and (c) corresponding EELS analysis (C: red, Si: green, O: blue). d HAADF-STEM images of the SiO2/FeNSiC (bright spots indicate the single metal atoms). e Images of Dark-field TEM observation and corresponding EDS elemental mapping for Fe (blue), N (cyan), Si (orange), O (yellow) and C (red) in the SiO2/FeNSiC sample. Source data are provided as a Source Data file.