Sol–Gel Synthesis of Porous Na₂Ti₆O₁₃: Effects of Polyethylene Glycol on Photocatalytic Degradation of Ofloxacin

Abstract Polyethylene glycol (PEG) modified Na 2 Ti 6 O 13 ( m = gram of PEG in the precursor) samples are synthesized via a sol–gel method to determine the effects of PEG on the porosity and activity of Na 2 Ti 6 O 13 . PEG prohibited the growth of Na 2 Ti 6 O 13 crystals in a rhombic system. The Na 2 Ti 6 O 13 ( m ) samples prepared using PEG are quite porous without large and dense particles. PEG obviously increased the porosity in Na 2 Ti 6 O 13 ( m ), while the specific surface area increased from 4.3 m 2 g −1 (Na 2 Ti 6 O 13 ) to 15.7 m 2 g −1 (Na 2 Ti 6 O 13 (1.5)), and the pore volume increased from 0.0072 to 0.0265 cm 3 g −1 at the same time. The bandgap energies of Na 2 Ti 6 O 13 , Na 2 Ti 6 O 13 (0.5), Na 2 Ti 6 O 13 (1.5) and Na 2 Ti 6 O 13 (2.5) are 3.15, 3.31, 3.53, and 3.58 eV, respectively. The photoluminescence intensities of the Na 2 Ti 6 O 13 ( m ) samples are in the reducing sequence: Na 2 Ti 6 O 13 , Na 2 Ti 6 O 13 (2.5), Na 2 Ti 6 O 13 (0.5) and Na 2 Ti 6 O 13 (1.5). The initial ofloxacin molecules in the solution are almost fully degraded after 70 min of irradiation using Na 2 Ti 6 O 13 (1.5), while the degradation efficiency of Na 2 Ti 6 O 13 is only 61.0% at the same time.