铁和镧共掺杂纳米二氧化钛光催化剂的制备、表征及其光催化活性

Preparation, Characterization and Photocatalytic Activity of Fe, La Co-doped Nanometer Titanium Dioxide Photocatalysts

以葡聚糖为模板，钛酸四正丁酯、硝酸铁和硝酸镧为前驱体采用模板法制备了一系列铁、镧单掺杂及共掺杂纳米TiO2光催化剂．利用SEM、XRD、BET比表面积测定t,uv—Vis等技术对其形貌、晶体结构及表面结构、光吸收特性等进行了表征．以甲基橙溶液的光催化降解为模型反应，考察了不同掺杂的样品在紫外和可见光下的光催化性能．TiO2材料具有较大的比表面积（约150m2／g），铁和镧共掺杂纳米TiO2在可见光区域有较强的吸收，在紫外和可见光条件下较纯TiO2和单掺杂TiO2对甲基橙溶液具有更好的光催化降解效果，且铁和镧的掺杂量显著影响该材料的催化性能．当铁掺杂量为0．5mol％、镧掺杂量为0．3mol％，在500℃焙烧2h所得光催化材料的催化性能最佳，焙烧4h即可使甲基橙的降解率达98．8％，且该复合材料有较高的循环回收利用率，重复使用4次仍可使甲基橙的降解率保持在88％以上．

A series of photocatalysts of un-doped, single-doped and co-doped nanometer titanium diox- ide （TiO2） have been successfully prepared by template method using Fe（NO3）3.9H2O, La（NO3）3.6H2O, and tetrabutyl titanate as precursors and glucan as template. Scanning electron microscopy, X-ray diffraction, and N2 adsorption-desorption measurement were employed to characterize the morphology, crystal structure and surface structure of the samples. The photo-absorbance of the obtained catalysts was measured by UV-Vis absorption spectroscopy, and the photocatalytic activities of the prepared samples under UV and visible light were estimated by measuring the degradation rate of methyl orange in an aqueous solution. The characterizations indicated that the prepared photocatalysts consisted of anatase phase and possessed high surface area of ca. 163-176 m2/g. It was shown that the Fe and La co-doped nano-TiO2 could be activated by visible light and could thus be used as an effective catalyst in photo-oxidation reactions. The synergistic effect of Fe and La co-doping played an important role in improving the photocatalytic activity. In addition, the possibility of cyclic usage of co-doped nano-TiO2 was also confirmed, the photocatalytic activity of codoped nano-TiO2 remained above 89.6% of the fresh sample after being used four times.