Synthesis of TiO2 nano-particles and their photocatalytic activity for formaldehyde and methyl orange degradation

TiO₂ 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 TiO₂ preparation was obtained. Results showed that particle sizes were in the range of 10–40 nm, and that prepared TiO₂ had better photocatalytic activity than P25. A simplified model was developed to evaluate the apparent quantum efficiency (Φ _app) of this photocatalytic reaction system.