fig1

Figure 1. (A) Schematic diagram of the fabrication route for Pt SA/NP hybrid electrode based on 3D-printed hydrogel templates; (B) SEM image of CS with (C) high-magnification views showing surface particulate residues. The areas outlined in red in (B) correspond to the magnified regions shown in (C); (D) SEM images of FCS with (E) high-magnification views showing the formation of hierarchical porous structures. The areas outlined in red in (D) correspond to the magnified regions shown in (E). SA: Single atom; NP: nanoparticle; 3D: three-dimensional; SEM: scanning electron microscopy; CS: carbon support; FCS: functionalized carbon support.