氮掺杂硅铝固载TiO_2多孔材料的制备及其光催化性能分析

Preparation of Nitrogen-doped TiO_2 Porous Materials with Silica-alumina Carrier and Its Photocatalytic Property

以硅、铝和钛的无机盐为初始反应物,采用水热法制得了具有光催化活性的氮掺杂硅铝固载TiO2多孔材料(N/TiO2-SiAl)。采用XRD、FESEM、FTIR、UV-Vis等现代分析技术分析表征了所得样品的物相结构及形貌;以甲基橙为探针在模拟太阳光下考察样品的光催化性能。结果表明:N/TiO2-SiAl为蜂窝状多孔材料,具有较大的比表面积;锐钛矿相TiO2以Si-O-Ti键的形式结合在无定形硅铝骨架中,并且硅铝骨架能够抑制锐钛矿相TiO2向金红石相转变;氮掺杂能够使TiO2的光响应范围向可见光区移动,在模拟太阳光照射120min后N/TiO2-SiAl对甲基橙的降解率达到90%以上,具有较高的光催化性能,重复使用4次后降解率依然在80%以上,具有较强的光催化循环使用性能。

Inorganic compounds containing SiO2, Al2O3 and TiO2 were used as initial reactants to form silicate framework and to carry TiO2. With urea as nitrogen source, the nitrogen-doped TiO2 porous materials with silica-alumina carrier （N/TiO2 SiAl） were fabricated first by hydrothermal method to form product precursor and then by follow-up sintering procedure. The phase configuration and morphology of the samples were characterized via XRD, FESEM, FTIR and UV-Vis diffuse reflectance. The photocatalytic activity to visible-light of the products was investigated using methyl-orange as the photodegrading compound. The results show that this material is featured of greater specific area and well-crystalline anatase octahedrite TiO2 uniformly distributed in the amorphous silica-alumina framework which can restrain the change from anatase to rutile. N doping could make the light absorption of the TiO2 obviously extended into visible-light region, and increase the visible-light responsive photocatalytic activity. The results of photocatalytic degradation of methyl orange show that the sample exhibits high photocatalytic activity under solar irradiation and methyl orange degraded more than 90% within 120 min. After four times repeat degradation, the degradation rate of methyl orange is still above 80%.