Versatile hierarchical Cu/Fe3O4 nanocatalysts for efficient degradation of organic dyes prepared by a facile, controllable hydrothermal method

Abstract

A novel monodispersed hierarchical nanocomposite catalyst of Cu/Fe₃O₄ was successfully synthesized through a short-time (just 4 h), facile, eco-friendly one-pot hydrothermal method. The as-prepared Cu/Fe₃O₄ nanocomposite was well characterized and the results showed that the products were spherical in morphology with diameters of about 100 nm. The BET surface area of the nanospheres was 37.16 m² g⁻¹, indicating that the product showed a porous character, and the major BJH pore size was 3.73 nm. The saturated magnetization of the Cu/Fe₃O₄ nanospheres was 48.0 emu g⁻¹, which facilitated their separation and recovery with the aid of an external magnet. In addition, the influences of experimental parameters such as the dosage of trisodium citrate dehydrate (Na₃Cit) and urea as well as reaction duration time were investigated in detail to fully elucidate the formation mechanism. More charmingly, the Cu/Fe₃O₄ nanocomposites exhibited excellent catalytic activity towards the reduction of hazardous organic dyes (4-nitrophenol, 4-NP; congo red, CR; methylene blue, MB) in aqueous media in the presence of NaBH₄ with very fast kinetics and good stability. The relationship between the Cu precursor addition amount and catalytic ability was also established. Considering the simplicity of the operation procedure, short time, low cost as well as easy recycling of the catalyst, this preparation protocol may shed light on the fabrication of other metal oxide materials; and hopefully, this hierarchical nanocomposite may find potential applications in other domains like heavy metal removal or antibacterial applications.