后处理法合成高热稳定性的中孔Ti-P-Al材料

 以阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)为模板剂,采用水热合成法制备了中孔氧化钛原粉,再采用磷酸和氯化铝溶液依次对中孔氧化钛原粉进行后处理,得到了具有高热稳定性的中孔Ti-P-Al材料. 通过粉末X射线衍射、透射电子显微镜和氮物理吸附等方法对样品进行了表征. 结果表明,反应凝胶组成对样品的中孔结构有较大的影响,当反应凝胶配比为Ti(SO4)2∶CTAB∶H2O=1∶0.54∶430, 温度为363 K, 处理时间为10～20 min时,所得的TiO2原粉具有较规整的中孔结构. 此样品经过0.25 mol/L的磷酸处理后有序性有较大程度的提高. 将磷酸处理过的样品进一步用氯化铝溶液处理,得到了中孔结构的Ti-P-Al材料,此材料经过873 K焙烧后仍具有典型的中孔特征,其比表面积为 382 m2/g, 孔径为3.13 nm.

Synthesis of Mesoporous Ti-P-Al Material with High Thermal Stability by Post-Synthetic Treatment

Mesostructured TiO₂ was prepared hydrothermally using cetyltrimethylammonium bromide (CTAB) as the structure-directing agent, and the mesoporous Ti-P-Al material with high thermal stability was subsequently synthesized by a two-step post-synthetic treatment. The sample was characterized by powder X-ray diffraction, transmission electron microscopy, and N₂ adsorption. The composition of the starting gel system greatly affected the mesostructure of the TiO₂ materials. With a gel composition of Ti(SO₄)₂:CTAB:H₂O = 1:0.54:430 and after being treated at 363 K for 10–20 min, an ordered TiO₂ mesostructure was obtained, which presented better long-range order after being treated with 0.25 mol/L phosphoric acid solution. Further treatment with AlCl₃ solution resulted in a mesoporous Ti-P-Al material with high thermal stability, which had a high BET specific surface area of 382 m²/g and a pore size of 3.13 nm after calcination at 873 K.