中文摘要：

光催化剂BaTinP2n＋1（n=1，2和4）粉末是通过sol—gel法制得的聚合物前驱体在800℃下烧制而成．利用XRD粉末衍射和UV—Vis吸收光谱表征样品的物相和吸收光谱特性．在样品的光催化活性测试中，采取甲基橙作为染料光降解的模型，研究了BaTiO3、BaTi2O5和BaTi4O9在各种酸性条件下对甲基橙溶液的降解效率，并初步探讨了其光催化性能差异的影响机制．实验表明，在相同的酸性条件下，三种钛酸钡BaTinP2n＋1（n=1，2和4）的光催化活性都随n的增大而增强，即BaTiO3〈BaTi2O5〈BaTi4O9．引入堆积率（定义为单位晶胞内所有组成离子的体积占整个晶胞体积的百分比）的概念，堆积率越小，则表明材料晶体结构越开放．利用结构开放度的概念模型可以很好地解释光催化活性的差异，即在这三种材料中，结构越开放，光催化性能越好．

英文摘要：

The BaTiO3, BaTi2O5 and BaTi4O9 photocatalysts were prepared by a sol-gel method calcined at 800℃. The prepared powders were characterized by X-ray powder diffraction and UV-Vis absorbance spectra. Their UV-induced photocatalytic activities were evaluated on the degradation of methyl orange at different pH values. The results show that the photocatalytic activities of BaTinO2n＋1 are improved as n increases from 1 to 2 and 4. The crystal packing factor （P.F.） is introduced to explain this phenomenon, in which P.F. is defined as the proportion of the total volume of all the ions in a cell to the volume of a cell. The smaller the P.F. is, the looser-packing the structure has, the better photocatalytie activity will be achieved. The experimental fact that BaTi409 has the best photocatalytic performance among the three compounds is ascribed to its highest structure-openness degree.