Pd-AgNbO_3光催化剂的合成及其光催化活性研究

Synthesis and Photocatalytic Activity of Pd-AgNbO_3

采用浸渍法制备Pd-AgNbO3光催化剂,并运用XRD、XPS、SEM-EDS和DRS等方法对光催化剂进行表征与分析。以亚甲基蓝染料(MB)为降解污染物,考察Pd掺杂对AgNbO3光催化活性的影响。结果表明,Pd引入后AgNbO3的晶型结构及表面性质并未发生变化。DRS分析表明,Pd掺杂后光催化材料在可见光区的吸光度明显提高。光催化降解实验表明,当Pd的掺杂量为0.8%(质量分数,下同),热处理温度为400℃,煅烧时间为3h时,光催化降解活性最高,MB降解率为92.2%。Pd-AgNbO3光催化降解MB符合一级反应动力学特性。

Pd-AgNbO3 photocatalysts were synthesized by an impregnation method. X-ray powder diffraction （XRD）, scanning electronic microscope （SEM） and energy dispersive X-ray spectrometer （EDS）, X-ray photoelectron spectra （XPS） and diffuse reflectance spectra （DRS） were employed to investigate the structure, morphology and photocatalytic properties of the photocatalysts. The photocatalytic activity of the samples was evaluated by degradation of methylene blue dye （MB）. The mechanism of enhancing photocatalytic activity was also discussed. The results indicate that Pd loading could not change the crystal structure and surface property of the AgNbO3 . The DRS analysis indicates that Pd loading increases the ability of visible light absorption of the catalysts. The Pd-AgNbO3 photocatalysts present the enhanced photocatalytic activity compared with the pure AgNbO3 . The photocatalytic efficiency is the highest when the sample with 0.8wt% Pd was calcined at 400 ℃ for 3 h and the MB degradation rate is 92.2%. The photocatalytic degradation of MB over the samples follows pseudo-first-order kinetics.