Fig. 2: Mesoscopic characterizations.

a Low-magnification SEM image, b TEM and c HAADF-STEM images, d high-magnification TEM and e HAADF-STEM images, and f HAADF-STEM EDS mapping images of SC-MHEO.

a Low-magnification SEM image, b TEM and c HAADF-STEM images, d high-magnification TEM and e HAADF-STEM images, and f HAADF-STEM EDS mapping images of SC-MHEO.