高热稳定性高有序性中孔Zr-P-Al材料的合成

Synthesis of Well-Ordered Mesoporous Zr-P-Al Material with Remarkable High Thermal Stability

以十六烷基三甲基溴化铵(CTAB)为模板剂,采用水热法合成了中孔氧化锆,依次用磷酸和水合氯化铝溶液对其进行后处理,得到了具有高热稳定性、高有序性的中孔Zr-P-Al材料.样品的XRD,TEM和氮气物理吸附测试结果表明,反应凝胶中的水量和陈化条件对样品结构有很大影响.当反应凝胶配比为Zr(SO4)2∶CTAB∶H2O=1∶0·27∶240时,所得样品具有较规整的六方结构.此样品经磷酸处理后,有序程度进一步提高.将磷酸处理过的样品再用水合氯化铝溶液处理,得到的材料具有典型的中孔特征和很高的热稳定性.最终产物经过700℃焙烧后具有416m2/g的比表面积,孔容积较大,孔径分布均匀,800℃焙烧后其比表面积仍可达到227m2/g.样品的高稳定性来源于锆、磷和铝之间的相互作用.

A well-ordered mesoporous Zr-P-Al material with high thermal stability (up to 800 degrees C) was synthesized using cetyltrimethylamnionium bromide (CTAB) as template by hydrothermal synthesis together with a two-step post-synthetic treatment. The samples were characterized by XRD, TEM and N(2) adsorption methods. It was found that the water amount in the starting gel system and the subsequent aging conditions greatly affected the structure of the material. With the gel composition of Zr(SO(4))(2): CTAB: H(2)O = 1 :0. 27:240 and aging at 80 degrees C for 4 h, a hexagonal zirconium oxide-sulfate was synthesized, which presented better long-range order after treated with phosphoric acid solution. Further treated with AlCl(3) solution, a mesoporous material with high thermal stability was prepared. The final material had a high surface area of 416 m(2) /g, regular pores with narrow pore size distribution and high pore volume after calcination at 700 degrees C. Even after calcination at 800 degrees C, the material still kept a BET area of 227 m(2) /g and the pore size distribution curve centered at 3.2 nm. The interaction among Zr, P and At was suggested to be responsible for the thermal stability of the mesoporous material.