Synthesis of TiO 2 and TiO 2 ‐Pt and Their Application in Photocatalytic Degradation of Humic Acid

The deposit of noble metal on titanium dioxide (TiO 2 ) has been considered as an effective strategy to improve the activity of TiO 2 . In this study, TiO 2 nanoparticles were prepared using a sol‐gel route followed by heat treatment at elevated temperatures (573 K, 773 K, and 973 K). TiO 2 ‐Pt catalyst (1 wt%) was prepared by depositing Pt on the surface of the prepared TiO 2 nanoparticles. TiO 2 and TiO 2 ‐Pt were used as heterogeneous catalysts to remove humic acid with UV‐light (120 W) illumination. TiO 2 prepared at low temperature with smaller particle size and larger specific surface area had stronger activity on humic acid degradation. Deposit of Pt would favor separation of photogenerated charges and enhance the photocatalyst activity, but its coating of the active site also inhibited degradation of humic acid. The addition of H 2 O 2 enhanced degradation of humic acid for more active oxygen produced. Low pH (pH = 4) was helpful to adsorb humic acid on the surface of TiO 2 and, correspondingly, enhance degradation of humic acid (44.4%).