Fig. 1. (a) SEM and (b) TEM images of g-C3N4. (c) SEM and (d) TEM images of P-g-C3N4. The selected region in red dashed square in (c) is enlarged and displayed in Fig. 4(a). The insets in (b) and (d) are schematic illustrations of overlapped nanosheets and porous sheet in the marked regions of g-C3N4 and P-g-C3N4, respectively.
