Green synthesis and characterization of gold nanoparticles embedded into magnetic carbon nanocages and their highly efficient degradation of methylene blue

Abstract

Currently tremendous efforts have been made to fabricate different noble metal nanoparticles (NPs) encapsulated in porous materials. Herein we present a general strategy for the preparation of coupled Fe₃O₄ and Au NPs into carbon nanospheres by employing diethylenetriamine as the coupling linker. Transmission electron microscopy images show that Au NPs were embedded into magnetic carbon nanospheres, and the mean particle size of Au is around 2.6 nm. The nanohybrids were used as catalysts to remove methylene blue from wastewater in the presence of NaBH₄. The results indicated that this catalyst exhibited superior catalytic activity toward methylene blue with a high degradation efficiency above 99% in aqueous solution, which is attributed to the high dispersity of the Au NPs into carbon nanospheres. Moreover, this catalyst showed good selectivity toward methylene blue in the presence of other pollutants. More importantly, the catalyst could be conveniently separated and recycled from the reaction mixtures using an external magnetic field, and the catalytic activity was still retained even over nine cycles. This work indicates that the nanohybrid could be a promising catalyst for the highly efficient and selective degradation of methylene blue from its dye mixtures.