Fig. 1: Characterizations of porous g-C3N4 few-layers.

a SEM image. b TEM image. c HRTEM image. d EPR. e–i XPS spectra of survey (e), C 1 s (f), N 1 s (g), O 1 s (h), and VB (i). j DRS spectra. k Tauc plot. l Energy band structure.
a SEM image. b TEM image. c HRTEM image. d EPR. e–i XPS spectra of survey (e), C 1 s (f), N 1 s (g), O 1 s (h), and VB (i). j DRS spectra. k Tauc plot. l Energy band structure.