The average size of the as-synthesized
CQDs is about 3–4 nm as observed from the HR-TEM images.
To investigate the surface functional groups of CQDs and their
interaction with TiO2 nanofibers, Fourier transform infrared
spectroscopy (FTIR) analysis was carried out and their spectra
were analyzed. Fig. 3 shows the absorption peaks around 500–
680 cm 1, 1626c m1, and 3440 cm1 for Ti–O vibration,O–H
stretching vibration, and O–H bending of water molecules absorbed respectively in TiO2 nanofiber [30,31].