复合碳纳米管增强纳米Ag_2CO_3的可见光催化活性和稳定性

Enhanced Visible-Light Photocatalytic Activity and Stability of Nano-Sized Ag_2CO_3 Combined with Carbon Nanotubes

在二甲基甲酰胺溶液中,通过简单的沉淀法制备了纳米Ag2CO3和碳纳米管(CNT)的复合物.用X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱、扫描电镜(SEM)和紫外-可见(UV-Vis)漫反射光谱(DRS)表征了所制备的Ag2CO3/CNT复合物,通过在可见光下降解甲基橙(MO)检测了样品的光催化活性.结果表明,纳米Ag2CO3颗粒与CNT结合良好.CNT的含量为1.5%(w)的Ag2CO3/1.5%CNT复合物活性最高,经过60 min的降解,甲基橙的降解率达到93%.与纯相纳米Ag2CO3比较,CNT的加入还提高了Ag2CO3的稳定性,经过三次循环降解,Ag2CO3/1.5%CNT复合物还能降解81%的甲基橙,而纳米Ag2CO3只能降解59.5%的甲基橙.其活性和稳定性提高的原因是由于CNT的高导电性,它不仅促进了电子-空穴对的分离,还能快速转移产生的光生电子.

Nano-sized Ag2CO3 and carbon nanotube （CNT） composites were fabricated by a facile chemical precipitation approach in N,N-dimethylformamide （DMF） solvent. The as-prepared Ag2CO3/CNT samples were characterized by X-ray diffraction （XRD）, Fourier transform infrared （FTIR） spectroscopy, scanning electron microscopy （SEM）, and ultra violet-visible （UV-Vis） diffuse reflectance spectroscopy （DRS）. The photocatalytic activity of the samples was evaluated by photocatalytic degradation of methyl orange （MO） under visible light irradiation. The results showed that the nano-sized Ag2CO3 particles and CNTs were well combined. The Ag2COJ CNT composite with CNT content of 1.5% （w） exhibited optimal photocatalytic activity under visible light. Ninety- three percent of the MO was removed by the Ag2CO3/CNT composite within 60 min. For the Ag2CO3/CNT composites, we found that the incorporation of CNT improved the structural stability of Ag2CO3 compared with Ag2CO3. After three cycles, 81% of the MO was decomposed by the Ag2CO3/CNT composite with CNT content of 1.5% （w）, but only 59.5% of the MO could be removed by Ag2CO3. The improvements in the activity and stability are attributed to the conductive structure supported by CNTs, which favors electron-hole separation and the removal of photogenerated electrons from the decorated Ag2CO3.