fig2
Figure 2. (A) Schematic illustration of synergistic fabricated ONPC materials; (B-D) SEM images of ONPC-700, ONPC-800, and ONPC-900, respectively. TEM images of ONPC-900; (D) low resolution; (E-G) high resolution, and (H) element mapping of C, N, and O. ONPC: O, N co-doped hierarchical porous carbon; SEM: Scanning electron microscope; TEM: Transmission electron microscope.
