Abstract: La-TiO₂ nanopowders were prepared by sol-gel method and further mixed with acrylic emulsion as binder to form the La-TiO₂ -based photocatalytic coatings via sand milling and ultrasonication. The particle size, specific surface area and UV-Vis absorption spectrum of La-TiO₂ nanopowder were characterized by XRD, BET and UV-vis spectrometer respeclively. The photocatalytic activity of the coatings was evaluated by the degradation of formaldehyde under UV irradiation. The effects of the type and content of photocatalyst the intensity o Uv-irradiation and the initial concentration of formaldehyde on the formaldehyde degradation rate of the coatings were investigated. The results showed that the optimal formaldehyde degradation rate (e.g.,71. 2% within 240 min )was achieved on the conditions of 500 W Mercury lamp, 1. 5% of La doping content, 8%of La-TiO₂ in the coatings, and 2 mg/m³ of initial concentration of formaldehyde.

Key words: formaldehyde, photocatalytic coatings, La-TiO₂, degradation

摘要：

采用溶胶－凝胶法制备 La-TiO₂光催化剂纳米粉体，以丙烯酸乳液为基体树脂，用砂磨机高速分散与超声辅助自制La-TiO₂光催化涂料。 利用 X 射线衍射仪、比表面及孔径分析仪和紫外可见光谱仪测定纳米粉体的粒径、比表面积及紫外可见漫反射吸收光谱。 以紫外光照射下涂料降解甲醛效果反映其光催化性能，并分别讨论了光催化剂种类与添加量、光照强度和甲醛初始浓度对涂料降解甲醛效果的影响，探讨了最佳光催化反应条件。 结果表明：在 500w 汞灯光照下，La 掺杂量为1.5%，La-TiO₂添加量为 8%，甲醛初始浓度为 2mg/m³时，降解效果最佳，240min内甲醛降解率达到 71.2%。

关键词: 甲醛, 光催化涂料, La-TiO₂, 降解