In this study we designed a novel, cost-efficient and green method for the synthesis of copper na-noparticles(Cu NPs)supported on manganese dioxide(MnO2)NPs,using Centella asiatica L.leaf extract as a naturally-sourced reducing agent, without stabilizers or surfactants. This synthetic process is environmentally-friendly and avoids the use of toxic reducing agents. Phenolic hydroxyl groups in the leaf extract are believed to reduce Cu2+ in solution to generate Cu NPs that are subse-quently stabilized on the MnO2NP surfaces. The resulting Cu/MnO2nanocomposite was fully char-acterized using X-ray diffraction, transmission electron microscopy, field emission scanning elec-tron microscopy, energy-dispersive X-ray spectroscopy and Fourier transform infrared spectrosco-py. This material was found to function as a highly active, efficient and recyclable heterogeneous catalyst for the reduction of Congo red, rhodamine B and methylene blue as well as nitro com-pounds such as 2,4-dinitrophenylhydrazine and 4-nitrophenol in the presence of NaBH4in aqueous media at ambient temperature. The high stability of the Cu/MnO2nanocomposite also allows the catalyst to be separated and reused several times without any significant loss of activity.%本文设计了一个经济、绿色的新型方法,采用积雪草树叶提取物作为自然的还原剂,在不使用稳定剂或表面活性剂的情况下合成了MnO2纳米粒子负载的Cu纳米颗粒(Cu NPs).该合成过程环境友好,且避免使用有毒的还原剂.树叶提取物中的酚羟基将溶液中的Cu2+还原为Cu NPs,后者再稳定在MnO2NPs表面.采用X射线衍射、透射电镜、场发射扫描电镜、能量散射谱和红外光谱对所得Cu/MnO2纳米复合物进行了表征.结果表明,该材料可用作高活性、高效可重复使用的多相催化剂,用于室温水溶液NaBH4存在下刚果红、罗丹明B和亚甲基蓝,以及硝基化合物,如2,4二硝基苯肼和4-硝基苯酚的催化还原.Cu/MnO2纳米复合物的高稳定性可使其被分离出来,重复使用数次而活性无明显下降.
展开▼
