Highly efficient photodegradation of 4-nitrophenol over the nano-TiO2 obtained from chemical bath deposition technique

Herein, we report the collection of TiO2 nanopowder after successful thin film deposition. The obtained TiO2 nanopowder was utilized for photodegradation of 4-nitrophenol (4-NP). The structural, optical, morphological, thermal and photocatalytic properties of TiO2 photocatalyst were systematically studied using XRD, Raman, HR-TEM, FT-IR, FE-SEM, EDS, UV–Vis, DRS, PL, BET and TGA. From XRD, we correlate crystallinity parameters like crystallite domain size, lattice cell parameters, unit cell volume, microstrain, stacking fault and dislocation density. TiO2 nanopowder annealed at 400 °C shows the anatase phase which is confirmed by Raman and XRD analyses. In addition, optical results indicate that the absorption band edge is positioned in the UV region with bandgap energy of 3.03 eV. The FE-SEM and TEM images of TiO2 nanopowder show irregular spherical morphology which results in the aggregation of nanoparticles with a mean diameter of 27 nm. From Brunauer–Emmett–Teller (BET) adsorption isotherm, the surface area was obtained to be 38 m2/g. The TGA curve demonstrates the thermodynamically stable anatase phase of TiO2 photocatalyst appeared in the 350–750 °C. Under UV light irradiation, photodegradation of 4-NP over 1.5 g/dm3 TiO2 photocatalyst dose achieved an excellent degradation efficiency and COD removal efficiency around 99.51 and 82% within 80 min, respectively. From trapping experiments, it indicates that OH· and O2· radicals are major reactive oxygen species involved in the photodegradation of 4-NP.