Fourier transform infrared spectroscopy (FT-IR) was employed to confirm the formation of COF@bio (Fig. ). The peak at 1632 cm⁻¹ indicated the successful formation of imine linkages (C=N), accompanied by a decrease in the C=O vibration band at 1683 cm⁻¹ and the ammonium salt (NH₃⁺) vibration bands at 3380-3280, 1578, and 1400 cm⁻¹. The C-O-C vibration band at 1270 cm⁻¹ was also present in the FT-IR spectra of both DFF and COF@bio, confirming the existence of the furan ring and reflecting the successful preparation of COF@bio. Furthermore, the Cross-Polarization Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (¹³C CP/MAS NMR) spectrum of COF@bio further validated the formation of the biomass-based COF (Fig. ). The spectrum displayed a resonance signal at 144 ppm, attributed to the C=N bond formation. Peaks at 149, 131, and 109 ppm corresponded to the carbons in the benzene and furan rings. All these peaks were identified in the synthesized COF@bio. Based on elemental analysis, the weight percentages of nitrogen, carbon, and hydrogen in COF@bio, CNT, and their composites are summarized in Table . Thus, the weight composition of COF@bio-40 can be inferred, showing that it comprises 57.3% CNT and 42.7% COF@bio. Fig. a) The FT-IR of the COF@bio and its monomers. b) the C CP/MAS NMR spectrum of COF@bio. c) The TGA curves of COF@bio, COF@bio-20, COF@bio-40, and CNT. d-e) the SEM of the COF@bio-40. f) the HRTEM of the COF@bio-40.