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

Abstract

We report a facile modification method to increase the visible light activity of TiO2 samples. We use titanium isopropoxide (TTIP) as the raw Ti source, hydrolyzing in acidic and alkaline solutions, respectively, to fabricate different TiO2 samples as raw TiO2 together with P25-TiO2. Only hydrogen peroxide and ammonia fluoride are used for this facile modification method, and three TiO2 samples are modified for the visible light degradation. This method could promote the transformation of crystalline TiO2 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, TiO2 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 TiO2 under visible light.