Fig. 1: Synthesis and structural characterizations.
a Synthesis procedure of ZOC. b Refined XRD of ZO and ZOC. c TEM image and d atomic resolution HAADF-STEM image of ZOC. e The line scan measured along the x-y rectangle region marked in d. f HAADF-STEM and corresponding EDS mapping images of ZOC. Green, red, and blue represent Zn, O, and Co elements, respectively. g Aberration-corrected HAADF-STEM image and corresponding atomic-resolution elemental maps (green and cyan correspond to Zn and Co atoms, respectively). h EELS mapping of the area enclosed by the red solid box in the inset of h (red pixels correspond to Co atoms). i EELS spectra acquired from the corresponding pixels in h. In g and h, the pixels highlighted by the yellow dashed and solid circles all correspond to Co atoms in the ZOC. j Normalized Co K-edge XANES spectra of ZOC sample, and standard Co foil, CoO, Co3O4, and Co2O3 as reference. k Normalized Zn K-edge XANES spectra of ZO, ZOC, and standard Zn foil and ZnO as reference. The inset shows the local enlargement of Zn K-edge XANES spectra. l FT k2 χ(R) Co K-edge EXAFS of ZOC, and standard Co foil, CoO, Co3O4, and Co2O3 as reference. m FT k2 χ(R) Zn K-edge EXAFS of ZO and ZOC, and standard Zn foil and ZnO as reference.
