Synthesis of ultrathin carbon dots-coated iron oxide nanocubes decorated with silver nanoparticles and their excellent catalytic properties

A facile ultrasonic method has been successfully developed for the fabrication of multifunctional Fe3O4@carbon dot/Ag (Fe3O4@C-dot/Ag) nanocubes (NCs), and the resulting materials are well characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), Vibrating sample magnetometer (VSM) and fluorescence measurements. The Ag nanoparticles (NPs) are uniform and well dispersed on the surface of Fe3O4@C-dot, while maintaining the shape and the size of the core-shell Fe3O4@C-dot NCs. In addition, its catalytic activities are evaluated by measuring the reduction of p-nitroaniline (p-NA) and crystal violet (CV), and the composite materials exhibit excellent catalytic activity towards reduction of p-NA and CV dye, which is superior to most reported catalysts. The good catalytic performance of Fe3O4@C-dot/Ag NCs may be attributed to the specific characteristics of its nanostructure and the synergistic effect on the delivery of electrons between Ag NPs and Fe3O4@C-dot NCs. Furthermore, the as-prepared catalysts also show good activity for the reduction of other nitrobenzene analogs. The effect of solvent and reducing agent was also studied on the catalytic activity of Fe3O4@C-dot/Ag NCs. Most importantly, the Fe3O4@C-dot/Ag catalyst shows excellent recycling stabilities, which can be potentially applied in the fields of catalysis and green chemistry.