Facile modification of TiO2 nanoparticles with H2O2 + NH4F for enhanced visible light photodegradation of rhodamine B and methylene blue

We report a facile modification method to increase the visible light activity of TiO 2 samples. We use titanium isopropoxide (TTIP) as the raw Ti source, hydrolyzing in acidic and alkaline solutions, respectively, to fabricate different TiO 2 samples as raw TiO 2 together with P25-TiO 2 . Only hydrogen peroxide and ammonia fluoride are used for this facile modification method, and three TiO 2 samples are modified for the visible light degradation. This method could promote the transformation of crystalline TiO 2 from rutile to anatase, increase the specific surface area, and the bandgap of samples shift to lower energy (2.2 – 3.0 eV) after the modification. For the visible light photodegradation tests, all the three modified samples show a higher visible light photodegradation efficiency. The highest kinetic constant of Rhodamine B and methylene blue degradation is 7 and 2 times that of P25, respectively. Additionally, TiO 2 fabricated by TTIP in alkaline solution and its as-modified sample show the highest adsorption of methylene blue dye, whose adsorption rate reaches 9 times that of P25. Thus, the present facile modification can effectively improve the photocatalytic ability of TiO 2 under visible light. • Modifying TiO 2 samples by a facile method using H 2 O 2 + NH 4 F. • All after-modification TiO 2 work better for RhB photodegradation. • Amorphous TiO 2 have high adsorption of MB.