可见光响应的Fe^(3+)修饰纳米TiO_2光催化降解氮氧化物研究

Photocatalytic Degradation of NO_x Under Visible Light Irradiation Using Fe Doped Titanium Dioxide

为了在光催化转化氮氧化物的反应中利用可见光,以Fe(NO3).9H2O作为Fe3+源,采用浸渍的方法,制备了Fe3+修饰的纳米TiO2。经XRD分析表明,搀杂和煅烧过程没有改变TiO2的晶型。由XRD和XPS图谱可知,Fe3+在TiO2表面形成Ti—O—Fe键。催化剂的UV-Vis漫反射光谱显示,Fe3+修饰TiO2催化剂的吸收光谱发生了一定程度的红移,在可见光区有一定的吸收。Fe3+修饰TiO2催化在蓝光照射下对NOx有一定的转化而且在模拟自然光下NOx的转化效率也有所提高。合适的Fe3+修饰量对修饰过程非常重要,Fe3+/Ti4+摩尔比为0.2%并在600℃下煅烧1.0 h的催化剂在可见光下转化NOx的活性最高。

In order to utilize visible light in photocatalytic conversion of NOx, Fe atoms were doped in commercially available photocatalytic TiO2 powders by impregnating method. The crystal phase of TiO2 was not changed after calcinations process. Analysis by both X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS） indicated that Fe atoms were incorporated in TiO2 as Ti-O-Fe linkages. A significant shift of the absorption edge to a lower energy and a higher absorption in the visible light region were observed. These Fe-doped TiO2 powders exhibited photocatalytic activity for the degradation of NOx under visible light irradiation. The sample mixed with 0.2% Fe^3＋ and calcined at 600 ℃ for 1.0 h showed the best photocatalytic activity.