论文部分内容阅读
研究了NH3气氛热还原处理两种TiO2光催化剂的形态(ATiO2,BTiO2)及其活性,400和500℃处理2 h的催化剂均显示黄色,而600℃以上处理则显示深灰色．以XRD、UV-Vis分析了NH3处理TiO2的结构,XRD表明ATiO2催化剂以锐钛矿和金红石混合晶型存在,而BTiO2只有锐钛矿型．UV-Vis结果发现NH3处理的两种TiO2在可见光区域都有很强的吸收．以甲基橙和苯酚研究了紫外光和太阳光下的光催化活性,结果表明NH3处理对两种不同制备方法的TiO2光催化活性影响存在显著差异,ATiO2随氨热处理温度提高活性降低,甲基橙50 min脱色率由400℃样品的100％逐步降到700℃样品的37％;而BTiO2随处理温度提高活性增加,甲基橙50 min脱色率由400℃样品的29％逐步提高到700℃样品的88％．在可见光下,ATiO2的活性与紫外光下规律相似,而BTiO2除了500℃样品外几乎都没有活性．最后对经过NH3处理的与未经处理的BTiO2活性进行了比较,发现NH3处理导致BTiO2光催化活性显著降低．
The morphologies (ATiO2, BTiO2) and the activity of two TiO2 photocatalysts treated by NH3 atmosphere were investigated. The catalysts treated at 400 and 500 ℃ for 2 h showed yellow color, while those treated at 600 ℃ showed dark gray color. The structure of TiO2 treated by NH3 was analyzed by XRD and UV-Vis. XRD indicated that the ATiO2 catalyst existed as a mixture of anatase and rutile while BTiO2 had only anatase. UV-Vis results showed that both TiO2 treated by NH3 have strong absorption in the visible region. Methyl orange and phenol were used to study the photocatalytic activity under ultraviolet light and sunlight. The results showed that there was a significant difference in the photocatalytic activity of TiO2 between two different preparation methods. The activity of ATiO2 with ammonia heat treatment decreased, Orange 50 min decolorization rate gradually decreased from 100% of 400 ℃ sample to 37% of 700 ℃ sample; while BTiO2 increased with the increase of treatment temperature, methyl orange 50 min decolorization rate gradually increased from 29% of 400 ℃ sample to 700 ℃ 88% of the sample. Under visible light, the activity of ATiO2 is similar to that under UV light, whereas BTiO2 has almost no activity except at 500 ° C. Finally, the NH3-treated and untreated BTiO2 activity was compared and found that the NH3 treatment resulted in a significant reduction of BTiO2 photocatalytic activity.