fig5

Figure 5. (A) HAADF-STEM image of Ru SA-Co-N-C, and the corresponding element contrast in randomly selected region (yellow A and blue B); (B) HRTEM image, (C) HAADF-STEM image, and the corresponding STEM-EDS of Ru SA-Co-N-C; (D) side views of atomic H adsorption on the Co-N-C and Ru SA-Co-N-C surfaces; (E) calculated free energy diagram on Co-N-C, Ru SA-Co-N-C and Pt for hydrogen evolution. Figures are quoted with permission from ref^[43]. Copyright 2022, Wiley-VCH. HAADF-STEM: High-angle annular dark field scanning transmission electron microscopy; HRTEM: high-resolution transmission electron microscopy; STEM-EDS: scanning transmission electron microscopy-energy dispersive X-ray spectroscopy.