Fig. 3: Characterizations of COF-DT, COF-DT-SO3H, and COF-DT-SO3Na.

a The experimental powder X-ray diffraction of COF-DT (blue line), the Pawley refined plot (yellow circle), and the difference between experimental and refined plot (purple line). b Comparison of experimental powder X-ray diffraction pattern of COF-DT (cyan line), COF-DT-SO3H (green line), and COF-DT-SO3Na (red line). c HR-TEM image of COF-DT. d Porous properties: N2 sorption isotherm of COF-DT (cyan circle line), COF-DT-SO3H (orange circle line), and COF-DT-SO3Na (green circle line).