fig5

Figure 5. Methodology of the defect engineering. (A) HAADF-STEM image of the defective area with atomic Ni trapped (left) and the corresponding illustration of a single Ni atom anchored on di-vacancy (right). Reprinted with permission from Ref.^[40]. Copyright 2018, Elsevier. (B) Top views of the optimized structures for CoN_4-xC_x. (I-IV) Represent four different coordination environments of cobalt atoms; I: CoN₁C₃, II: CoN₂C₂, III: CoN₃C₁, IV: CoN₄. Reproduced with permission from Ref.^[41]. Copyright 2020, Wiley-VCH. (C) STEM image together with the line profiles extracted from the areas marked with purple rectangles of a monolayer MoS₂ flake film after etching. Reprinted with permission from Ref.^[45]. Copyright 2020, American Chemical Society. (D) HAADF STEM images of a Ti_0.87O₂ nanosheet (left) and line profile exhibiting a clear intensity variation of atomic columns (right). The arrows indicate the Ti vacancies. Reprinted with permission from Ref.^[46]. Copyright 2018, American Chemical Society.