fig4

Figure 4. Schematics of the preparation of (A) C₃N₄-D and (B) Cu₂@C₃N₄-D. AC-HAADF STEM images of (C) Cu₂@C₃N₄-D1, (D) Cu₂@C₃N₄-D2, and (E) Cu₁@C₃N₄-D1. (F) and (G) Atomic distance from the selected areas in (C) and (D), respectively. (H) Elemental distribution of C, N and Cu on Cu₂@C₃N₄-D1. Scale bars are 1 nm for c-e and 10 nm for h, respectively^[81]. Copyright 2021, Elsevier. AC-HAADF-STEM: Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy; STEM: scanning transmission electron microscopy; nm: nanometer.