Synthesis of TiO 2 nano-particles and their photocatalytic activity for formaldehyde and methyl orange degradation

TiO 2 nano-particles were synthesized by sol-gel technique and characterized by X-ray diffractometer (XRD) and transmission electron microscope (TEM). Their photocatalytic activities for formaldehyde (FA) and methyl orange (MO) degradation were tested using degradation rate ( η ) as an evaluation index. Based on the orthogonal test results, the optimal condition for TiO 2 preparation was obtained. Results showed that particle sizes were in the range of 10–40 nm, and that prepared TiO 2 had better photocatalytic activity than P25. A simplified model was developed to evaluate the apparent quantum efficiency ( Φ app ) of this photocatalytic reaction system.