fig4

Figure 4. (A) Model for single-atom Ni-decorated Pt (111) surface, with the Ni atoms in the surface layer. This figure is quoted with permission from ref^[35]. Copyright 2019, Springer Nature; (B) HAADF-STEM image and (C) aberration-corrected HAADF-STEM image for single atom In decorated Pt nanowires. Figures are quoted with permission from ref^[36]. Copyright 2020, Wiley-VCH; (D) TEM image of the Pt/Ni catalyst, (E) HAADF-STEM image and (F) magnified aberration-corrected image obtained from the white square in (E); (G) free adsorption energies of H over Pt-Ni-hcp and Ni-hcp; (H) corresponding dissociation–diffusion–desorption mechanism for hydrogen evolution over Pt-Ni-hcp. Figures are quoted with permission from ref^[38]. Copyright 2021, American Chemical Society. HAADF-STEM: High-angle annular dark field scanning transmission electron microscopy; TEM: transmission electron microscopy.