fig7
![Hollow microstructural regulation of single-atom catalysts for optimized electrocatalytic performance](https://image.oaes.cc/dc28578d-4b62-4a6e-9070-b77b2ea44a6e/4414.fig.7.jpg)
Figure 7. (A) Schematic illustration of the formation of Ni-NC@Ni. (B) HAADF-STEM and (C) AC HAADF-STEM images of Ni-NC@Ni. (D) High-resolution Ni 2p and (E) N 1s XPS spectra of Ni-NC@Ni (inset: atomic structure)[122]. AC HAADF-STEM: Aberration-corrected high angle annular dark field scanning transmission electron microscopy.