超声辅助法制备银纳米球及其对亚甲基蓝的催化降解研究 Ultrasonic Wave Assisted Synthesis of Silver Nanospheres and Their Catalytic Degradation on Methylene Blue

本文以银氨溶液为银源，抗坏血酸(C6H8O6)为还原剂，聚乙烯吡咯烷酮(PVP)为表面活性剂，在超声辅助条件下，采用了简单环保的室温液相还原法制备出了形貌均匀、分散性良好、粒径为300~400 nm的银纳米球，用X射线粉末衍射、能量分散X射线谱、扫描电子显微镜和紫外–可见分光光度计对合成产物进行了表征。通过改变超声时间、PVP的用量和氨水体积来研究产物的形貌变化。分析了银纳米球的生长过程，提出了可能的生长机理。测试了样品对亚甲基蓝的催化降解性能，结果表明，制备的银纳米球对亚甲基蓝有良好的催化降解效果。 A facile environmental friendly method has been developed to prepare silver nanospheres with good dispersion and the size in the range of 300 - 400 nm. Silver nanospheres were obtained via the chemical reduction of Tollens’ reagent at room temperature, using ascorbic acid as the reducing agent and polyvinylpyrrolidone (PVP) as the surfactant. The obtained silver nanospheres were characterized by X-ray powder diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and UV-visible spectroscopy (UV-vis). The influence of reaction time and the amount of PVP and ammonium hydroxide on the formation of silver nanospheres was studied. The growth process of silver nanospheres was analyzed and the possible mechanism of crystal growth was proposed. The catalytic degradation activity of the obtained silver nanospheres on methylene blue was also measured. They showed excellent catalytic degradation activity on methylene blue.