镧、碳共掺杂TiO2的制备及其可见光催化性能

为了更有效地利用太阳能，以钛酸丁酯为前驱体，硝酸镧和四丁基氢氧化铵为掺杂离子给体，通过改进的溶胶-凝胶法，成功制备了纯TiO₂和不同掺杂浓度的镧、碳掺杂和共掺杂TiO₂光催化剂.表征结果显示，共掺杂催化剂为锐钛矿型，具有较高的比表面积，感光范围拓展到可见光区.分别以甲基橙、罗丹明B和4-氯酚为降解物，氙灯、太阳光和自然光为光源，进行催化剂的光催化降解实验，结果表明，共掺杂催化剂活性高于未掺杂和单掺杂催化剂.降解结果显示，当共掺杂催化剂含0.5% La³⁺(摩尔比)、焙烧温度在500℃时具有最高的光催化降解效率.共掺杂TiO₂具备较高的可见光催化活性原因可能是碳掺杂降低了TiO₂禁带宽度，而镧掺杂同时维持了体系的电荷平衡.

Preparation of lanthanum and carbon co-doped TiO2 and photocatalysis under visible irradiation

TiO₂-based photocatalysis technology was developed and applied to photodegradation of organic contaminants by utilizing solar energy effectively.Pure and doped or co-doped TiO₂ catalysts with various amounts of lanthanum and carbon were obtained by a modified sol-gel process, in which tetrabutyl titanate was used as precursor and lanthanum nitrate, tetrabutylammonium hydroxide as ion donors.The as-prepared photocatalysts were found to be of anatase phase, higher specific area, and visible response by means of XRD, BET and UV-vis spectra analysis.The co-doped TiO₂ catalysts showed higher photocatalytic activity in degradation of rhodamine B, methyl orange and 4-chlorphenol under Xe lamp, sunlight or daylight irradiation than that of pure and single doped ones.Photodegradation experiments showed that the co-doped catalyst with 0.5% (molar ratio) lanthanum calcinated at 500℃ was of the highest catalytic efficiency under visible irradiation.The higher visible light photocatalytic activity of co-doped TiO₂ was attributed to the doped carbon that lowered the ban